Comparison of schedule delay and causal factors between traditional and green construction projects.

Hwang, Bon Gang ; Leong, Lay Peng

Introduction

The construction industry is a key economic growth sector in Singapore and plays a dominant role in providing employment to support the future development of Singapore (Navon 2005). According to the Building and Construction Authority (BCA) (Building and Construction Authority 2011), the value of construction contracts to be awarded in 2011 and 2012 would be between $18 and $25 billion, and it will continue to escalate over the next 2-3 years.

With the mounting global concern on the environment, Singapore has also shifted its focus to making sustainable development a key national priority as well (Singapore Green Building Council 2009; Kua 2006; Hwang, Tan 2012). Green building is believed to be a more eco-friendly approach in most aspects. Since the launch of BCA's Green Mark Scheme in 2005, the number of green mark certified buildings have increased to 440 from the mere 17 in 2005 (The Business Times 2010). In addition to the green mark scheme, BCA also formulated the 1st and 2nd Green Building Masterplan together with other efforts to thrust forward in developing more green buildings in Singapore. By year 2030, the Inter-Ministerial Committee on Sustainable Development (IMCSD) targets to have at least 80% of the building in Singapore to achieve the BCA green mark certified rating (BCA 2009). Furthermore, in order to intensify the efforts in speeding up the development of green buildings in Singapore, all new building developments and major renovations which are over 2000m2 in size are required to achieve green mark certifications (Building and Construction Authority 2008). As such, construction of green buildings is gaining greater foothold in the recent years in Singapore.

With the rising number of green building construction projects, it is necessary to ensure that green building projects are completed on time and delivered successfully. A project is considered successful if it is completed on time, within budget and meeting the required quality standards specified by the client (Chan, Kumaraswamy 1996; Walker 1995). Furthermore, projects, in particular, that are completed on time are an indicator of an efficient construction industry (Male 1988). Positive construction time performance ensures that a project can be completed within the stipulated time or earlier. This will reduce the amount of overhead cost and provide a higher opportunity for the client to generate revenue at an earlier stage.

As green building construction continues to grow and gain popularity, there is a need to better understand schedule performance of green building construction projects. Comparing with traditional building projects, this study aims to: (1) investigate the degree of project delay in comparison between traditional and green projects; (2) analyze the causal factors of delay for both green and traditional projects; and (3) to discuss the possible solutions for the delay problems of green projects.

1. Background

1.1. Green buildings

The construction of green building is part of sustainable construction. According to Kibert (2008), sustainable construction addresses the ecological, social and economic issues of a building in the context of its community. Sustainable construction is applied throughout the entire life cycle of construction, from preconstruction to disposal of the building. Such construction aimed to reduce the impact of the construction practice on the environment through its planning and managing of a construction project complying with the contract document (Glavinich 2008; Pitt et al. 2008).

In most literature, the term green building is defined as an environmentally sustainable building which is constructed with minimal environmental impacts. This is further supported by Glavinich (2008) who defined green building as a building that provides the required building performance criteria while minimizing disturbance to and improving the ecosystems in the local, regional and global context throughout its entire building life cycle. Green buildings are healthy facilities which are designed and built in a resource efficient manner using ecologically based principles (Kibert 2008).

1.2. Green building construction industry

Since the inception of Green Mark Scheme together with the 1st and 2nd Green Building Masterplan, Singapore has experienced a concerted shift towards the development of green buildings (Hwang, Ng 2013; Tobias 2010). The sharp growth in the number of BCA Green Mark Certified new buildings in 2007 is an evident success of the BCA's 1st Green Building Masterplan which was launched in 2006 (Building and Construction Authority 2009). The thrust towards more buildings being certified with Green mark has grown beyond Singapore to overseas such as Thailand, Vietnam, Indonesia, and China (BCA 2009). At present, statistics from the BCA green mark webpage revealed that there are a total of 326 green mark certified buildings in Singapore where 52 buildings are awarded with green mark platinum, 36 green mark goldplus certified, 134 green mark gold certified and 104 green mark certified buildings (BCA 2010).

According to BCA (2010), Green Mark provides a meaningful differentiation of buildings. The benefits of having a BCA Green Mark building include a reduction in water and energy bills; an improvement in indoor environmental quality for healthy living; and a reduction in potential negative impact on the environment. In addition, green building offers a reduction lifecycle costing in its operation and maintenance cost as well (Kats et al. 2003).

It is widely known that green building projects contributes to environmental sustainability and greater human health benefits to its occupants. Research has proven that with minimal increase in upfront cost of about 2% to incorporate green designs in building, it will result in lifecycle savings of 20% of total construction cost on an average which is more than ten times the initial investment (Kats et al. 2003). For that reason, it is worthy to consider the implementation of green building design as compared to traditional building design.

1.3. Green building schedule performance

It is important that green requirements are well addressed and reflected in project schedule to avoid any schedule delays. As noted by GreenBiz Group (2005) and Kats et al. (2003), design and construction process of green building construction usually takes longer than traditional building construction. This is due to the reason that project team members require more time to be familiar with and implement green building practices. Also, design documents are required to be more comprehensive before the start of construction, as more time is necessary for architectural and engineering designs to integrate green building practices into the project. This will have an impact on the project schedule and may increase design cost (Kats et al. 2003).

In addition, green requirements have an effect on schedule of procurement, construction, and project closeout and commissioning (Glavinich 2008). Contractors have to ensure that local and imported materials used for green construction meet preset-standards and are delivered without delays. During construction, green requirements and constraints can have a great influence on the construction sequence and duration as well. For example, installation of HVAC ducts is mounted before the building under construction is enclosed while in green building construction, to prevent any dust and moisture contamination, the building is enclosed before installation of the ducts. As such, it can be seen that green requirement may pose an impact on construction schedule and such requirements are needed to be indicated in the schedule to prevent any problems causing delay.

1.4. Factors causing project delay

While completing projects on time is an indicator of efficiency, construction processes are subject to various and unpredicted factors that can cause delay (Assaf, Al-Hejji 2006). Construction delay was defined by Assaf and Al-Hejji (2006) as schedule overruns either beyond completion date specified in the contract, or beyond the date that the parties agreed upon for the delivery of the project. In today's construction industry, it is known that project delay is an international common problem (Assaf, Al-Hejji 2006; Chan, Kumaraswamy 1996; Hwang, Lim 2013; Hwang et al. 2013; Odeh, Battaineh 2002). In Australia, Bromilow (1974) found that only one-eighth of the building contracts were completed within the scheduled completion dates and the average construction time overrun exceeded by 40%. Assaf and Al-Hejji (2006) identified that 70% of the large projects in Saudi Arabia experience time overrun. It was found that the average time overrun of projects is between 10-30% of the original duration. In Hong Kong, Chan and Kumaraswamy (1995) observed that almost 70% of the public and private building projects were completed behind schedule. Ogunlana et al. (1996) conducted a research on construction delay in Thailand and found that residential projects experienced an approximate of 34.33% delay from the original schedule and 11.33% for office buildings. In Malaysia, Sambasivan and Yau (2007) mentioned that about 17.3% of the 417 government contract projects were considered sick (more than 3 months of delay or abandoned) in 2005.

There are several studies (Mansfield et al. 1994; Chan, Kumaraswamy 1997; Nguyen et al. 2004; Walker 1995; Assaf, Al-Hejji 2006; Alaghbari et al. 2007; Sambasivan, Yau 2007; El-Razek et al. 2008; Choi 2009; Zhang 2011) that evaluated and classified the factors that affect project schedule and delay.

Based on the literature reviewed, this study identified 38 factors and grouped them into 8 major categories. More details of the factors and categories are discussed below and summarized in Table 1.

1.4.1. Project related factors

Factors in this category include the project delivery methods, the lack of communication between all the project team members, or the speed of decision making involving all projects teams. Chan and Kumaraswamy (1997) found that low speed of decision making involving all project teams is the third most significant factor that caused project schedule delay. The right selection of project delivery methods can reduce defective design, and improve coordination between project members, ultimately enhancing project schedule performance and preventing project delay (Eriksson, Westerberg 2011).

1.4.2. Client related factors

Clients play an important role in construction projects. The client is one of the key drivers to ensure that a project is completed successfully (Thompson 1991). From the research conducted by Assaf and Al-Hejji (2006), client related factor category was ranked first with regard to the impact on schedule delay. Client initiated variation in this category was deemed as one of the top five most significant delay factors across numerous studies. Bromilow (1974) found that clients contributed to 41% to the overall variations in projects. Client initiated variation was identified as the fourth important cause of delays by Chan and Kumaraswamy (1996). Furthermore, the financial issues caused by clients were considered the main cause of delay by Ahmed et al. (2003) and Abdul-Rahman et al. (2011).

1.4.3. Consultant related factors

Consultants such as project managers and engineers hold great responsibilities in the project. Consultant related factor category was ranked third in the study by Assaf and Al-Hejji (2006). It was specified that consultants should review and approve design documents timely prior to construction phase to avoid any delay.

1.4.4. Design team related factors

Researchers found differing perceptions on the relative impact of schedule delay by the various project team members. Nonetheless, design team related factor was deemed as the most influential factor category on project delay by the contractors in the studies by Chan and Kumaraswamy (1997) and Assaf and Al-Hejji (2006).

1.4.5. Contractor related factors

Alaghbari et al. (2007) studied the significant factors causing delay of building construction projects in Malaysia and had identified that the contractor related factors were first in rank. This was further supported by the research conducted by Chan and Kumaraswamy (1996). Therefore, main factors attributed by contractor which pose great impact on the project schedule consist of the contractor's financial capability to finance the project and the ability to manage and supervise the construction site properly.

1.4.6. Labor related factors

Labor related factors were identified as the top 10 factors affecting project schedule in research by El-Razek et al. (2008), Arditi et al. (1985), Mansfield et al. (1994) as well as by Assaf and Al-Hejji (2006).

1.4.7. Equipment and materials related factors

Shortage of equipments and/or materials can cause severe stoppage of work leading to project delay. Late delivery of material and plants factor was ranked the highest in a research conducted by Majid and McCaffer (1998). Similarly, materials and equipment related factors affecting schedule was second in rank as investigated by El-Razek et al. (2008).

1.4.8. External factors

External related factors especially unforeseen ground conditions was rated as the top 3 most significant factors affecting project schedule by Chan and Kumaraswamy (1996). Unexpected ground conditions include poor soil condition, underground obstruction, hard rock barriers and inaccurate estimation of groundwater flow. This might be due to the fact that most projects were rushed into commencement, which resulted in inadequate feasibility studies (Mansfield et al. 1994).

1.5. Implications

Although there have been several researches carried out to evaluate schedule performance of traditional construction projects, there is limited literature that has explored schedule performance of green building construction projects. Similarly, the factors causing schedule delay of green projects have been rarely studied. Therefore, there is a need to examine project schedule performance of green building projects, identifying various factors that cause the delay of these projects.

2. Methodology and data presentation

To achieve the objectives of this study, a comprehensive literature review was first conducted. After gaining an understanding of green building construction and its progress in the construction industry as well as the factors that cause project schedule delays, it was recognized that input from industry practitioners are needed in order to ensure that this study can represent the overall green building construction position. As a result, a survey questionnaire was developed.

The findings from the literature review supported the development of the questionnaire that consisted of four sections capturing: (1) the profile of the participating companies and respondents (2) the information of traditional and green building projects performed by the companies; (3) the factors causing schedule delays; and (4) the solutions for improving green building schedule performance. The questionnaires were sent out via email to construction, consulting, development, and quantity surveying companies registered in the directories of BCA and Singapore Institute of Surveyors and Valuers. As the BCA green mark scheme commenced in 2005, the target of the survey was the companies that had experience in both green and traditional projects performed in years of 2005 to 2010.

Using the data obtained from the survey, analyses on frequency, descriptive mean scores, and Spearman's ranked correlations were performed to determine the degree of schedule delays in traditional and green building construction projects as well as the relative association of the ranking of different factors causing delays. The respondents were asked to provide the total number of traditional projects they performed for the last five years, followed by the numbers of the projects that had experienced schedule delays. For the green building projects, the respondents provided the same. Also, the respondents selected an appropriate rating based on a defined scale to reflect on the importance level of each of the listed factors. The scale was based on a five-point Likert scale with '1' being 'not important' and '5' being 'very important'. Similarly, the five-point Likert scale was also used to evaluate the effectiveness of the recommended solutions to improve green building project schedule performance.

In addition, the Spearman rank correlations were calculated and tested to see if the relative importance of the factors affecting delays of green building projects is significantly correlated with that of traditional construction projects. The test was performed at the confidence level of 0.05.

As a result of the survey, 30 completed questionnaires were returned. A summarized profile of the companies and respondents that participated in the survey is presented in Table 2.

3. Data analysis and discussions

3.1. Comparison of schedule delays

The companies were asked to input the number of traditional and green building projects that they had performed as well as the number of projects delayed. The analysis further broke down the projects based on project type, nature and size to understand how the characteristics of projects affect the project schedules.

As seen in Table 3, the overall percentage of projects that had been delayed were 15.91% and 32.29% for traditional and green building projects respectively. It can be inferred that green building construction projects have a higher probability of delays as compared to traditional building projects. As green building construction projects require green technologies which are still relatively new to the industry, it requires more time to understand and incorporate these technologies into the design. This is further supported by Snell and Callahan (2005) as they pointed out that green building construction takes much longer to complete and presents more challenges than anticipated even if builders are highly experienced at construction, design and creative problem-solving.

In terms of specific project type, commercial building projects accounted for the highest frequency of delay for both the traditional (25.00%) and green (57.14%) building projects. This may be due to the fact that commercial projects are relatively unique in nature and vary widely in terms of requirements, design and specifications when compared to residential or educational buildings that can be easily modeled based on past projects. In comparison between the percentage of delay in traditional and green building projects, the percentage of delay for green commercial projects (25%) was more than twice of traditional commercial building projects (57.14%). One possible reason for a higher delay occurrence in green commercial building projects may be the complexity in incorporating green technologies into the building systems.

Table 3 also presents the percentage of projects that were delayed by project nature, namely, new construction and addition/alteration. It can be seen that more new construction projects were delayed than addition and alteration projects for both traditional and green building projects. This result could be expected as new construction projects have higher level of uncertainty attributed by the wider scope of the projects than that of addition and alteration projects. It is also observed that new green building construction (33.33%) may encounter the higher likelihood of delay than traditional building construction (17.39%). As the green building construction is still relatively new to the construction industry, it may be more difficult for the players in the industry to manage this type of green building projects.

Furthermore, large-sized projects in terms of contract amount had a higher tendency to encounter project delay. The projects costing $50 million and above reported the highest percentage of delay for both traditional (29.17%) and green projects (40.63%). With more project parties involved in large construction projects, relationships and flow of information among project team members become more complicated, and inadequate and ineffective coordination can increase the likelihood of communication breakdown and variations, leading to project delay (Nguyen et al. 2004). Large green building projects, in particular, may require more effective coordination and collaborators than traditional projects due to the complexity inherent in usages of new processes and technologies, and this aspect is reflected at the analysis result.

3.2. Factors affecting project schedule delays

Having investigated the degree of project delay occurred in traditional and green building projects, it became apparent that identifying various factors responsible project delay is necessary to improve schedule performance. As a result, the relative importance of the factors regarded by the respondents as major causes of project delay was analyzed for traditional and green building projects. The analysis results are presented in Table 4.

3.2.1. Project related factors

Under traditional building projects, factor P4 yields the highest mean score of 4.53 as seen from Table 4. It can be interpreted that the respondents considered communication and coordination between key parties as the upmost important factor that will affect the project schedule to a large extent. Since factor P3 with mean score of 4.53 is relatively close to the mean score of factor P4, it can also be derived that the speed of decision making involving all project teams is also a critical factor that may affect the project schedule. Factors P1 and P2 are ranked an average of close to a mean of 4.0 showing a degree of importance as well. However, factor P5 has the lowest rank of mean score 3.17 which signified that legal disputes and conflicts between key parties weighs a small percentage of importance that may affect the project schedule.

For green building construction project, the most influential factor which may cause delay in project schedule is attributed by factor P3 with a high means score of 4.77. Although factor P4 is second in rank with mean score of 4.70, the close mean score between the two factors illustrates that factor P4 is as important as factor P3. Similar to traditional projects, P1 and P2 are ranked with an average of 4.30, while factor P5 is lowest in rank denoting that it has the lowest impact on project schedule.

The 3rd, 4th and 5th rank of the factors under the project related factors between traditional and green building projects are consistent. In contrast, the first and second rank of the project related factors for the two groups are inverted. Since the top two factors between traditional and green building projects have mean score of more than 4.5, it can be implied that communication/ coordination between key parties is required to ensure that decisions making between key parties can be determined promptly to avoid project delay.

To further examine the agreement of the ranking of the project related factors between traditional and green building projects, the spearman's correlation coefficient of 0.895 was obtained. This shows a positive correlation between the ranking of the project related factors under traditional and green building projects since a high value of rank correlation coefficient suggests a strong agreement between the two groups. Since the p-value of 0.04 at 95% significance level is less than the significance, [alpha] = 0.05, this shows that there is significant relationship between the traditional and green building projects for factors that are project related. Agreement between the rankings of the factors for both groups is observed as the respondents may feel that the extent of effect by the individual factors is similar for both traditional and green building projects.

3.2.2. Client related factors

With reference to Table 4, the ranking of client related factors between traditional and green building projects is identical. Respondents agreed that the speed of decision making by client has the highest effect on schedule delay in this category. Factor CL3 with mean scores of above 4.5 for both traditional and green projects suggest that it has considerable effect on project schedule as well. Therefore, to ensure positive schedule performance, the client's speed on decision making and level of experience is vital to ensure that the schedule is without delay.

Under green building projects, all the client related factors have mean scores which are above 4.00. This illustrates the fact that the client's impact on schedule is of great magnitude and should not be overlooked.

The Spearman's rank correlation coefficient of 1.00 indicates a positive correlation between the two groups. Since the p-value of 0.000 at 95% significance level is less than the significance, [alpha] = 0.05, it implies that there is a strong agreement in the ranking of the factors under the client related categories. There is strong agreement on the rankings of the impact of the factors affecting project schedule under the two groups as the level of client involvement might be similar for the two types of projects. It might also be due to the fact that each factor has equal impact on traditional and green project schedule.

3.2.3. Design team related factors

Factor DT1 has the highest ranked mean of 4.47 under traditional building projects. It is followed by factor DT3, DT2 and DT4 respectively. Amongst all the design team related factors, mistakes and delay in producing design document has the highest influence in causing the project schedule to be delayed. For green building projects, factor DT2 with mean score of 4.63 is ranked the highest with factor DT3, DT1 and DT4 ranked behind in accordance. Level of design team experience is top in rank under green building projects as team members should be familiar with the specifications of green technology when it is incorporated into the design of the building systems.

The Spearman's rank correlation coefficient of 0.20 indicates a weak correlation between the two groups. In addition, since the p-value of 0.600 at 95% significance level is more than the significance, [alpha] = 0.05, it implies that there is no significant relationship and insubstantial agreement in the ranking of the factors under the client related category between the two groups. As such, we can conclude that the severity of the factors varies according to traditional and green building projects.

The disparity of the ranking between the two groups may be because more emphasis is placed on the design of green building construction project. According to Kubba (2010), green buildings are progressively incorporating more advanced and intricate systems of interacting elements. During design, the impact of the elements on each system must be considered as a whole. A failure to take into account the integration of green technologies and its impact on other building elements would result in construction conflicts leading to delay to address such problems. As such, the levels of experience of the design team as well as complexity of the design have the highest impact on green building project schedule as compared to traditional building project.

3.2.4. Consultant related factors

Under traditional building projects, factor CS3 of mean 4.60 is ranked first, followed by factor CS2, CS1 and CS4 correspondingly. Factor CS5 of mean 4.70 is considered to have the highest impact on green project schedule amongst all the consultant related factors. It is similar to that of design team related factors for green building projects, where level of design team experience is considered the factor with the highest impact on project schedule delay.

The Spearman's rank correlation coefficient of 0.70 indicates a fairly strong correlation between the two groups. However, the p-value of 0.188 at 95% significance level is more than the significance, [alpha] = 0.05. It implies that there is insufficient agreement and relationship on the ranking of the factors between the two groups although the rank correlation coefficient is relatively strong. As such, it is deduced that the severity of the factors varies according to traditional and green building projects.

Level of experience of the consultant team is important under green building construction projects as the level of design complexity is higher as compared to traditional building projects. With reference to Kubba (2010), specialist consultants should be involved in the design process earlier to incorporate their suggestions and requirements in the design such that that their contributions are taken into account to safeguard maximum efficiency. Therefore, without the required level of knowledge and experience by the consultants, the harmonization of the systems would not be possible and risk the chances of having conflicts. In addition, a delay in reviewing and approving the design would further impede the project schedule.

3.2.5. Contractor related factors

With reference to Table 4, factor C[O.sub.3] is deemed as the most influential factor on project schedule delay for both traditional and green building projects. The mean score of factor C[O.sub.3] under traditional building project is found to be 4.40 and 4.70 under green building projects. Factor CO1 and C[O.sub.2] are ranked second and third interchangeably for both groups as seen in Table 4. It is noted that aside from the incapability of financing the project which would cause the project schedule to be delayed, good site management and supervision accompanied by the ability to plan and monitor project schedule appropriately is vital to ensure that optimal project schedule performance is met.

The Spearman's rank correlation coefficient of 0.90 indicates a strong correlation between the two groups. As, the p-value of 0.005 at 95% significance level is less than the significance, [alpha] = 0.05, it indicates that there is adequate agreement and significant relationship on the ranking of the level of impact of the contractor related factors between traditional and green building projects. Similar rankings on the level of impact of the contractor related factors for both green and traditional projects as it is perceived that the degree of influence of the variables associated with contractor is unaffected by the type of project.

3.2.6. Labor related factors

In this category, the statistics showed that there is unanimous agreement by the respondents on the level of impact between the three factors on traditional and green building projects. Factor L1 is regarded as having the highest impact on project schedule for both traditional and green building projects, while factor L2 and L3 are ranked second and third respectively.

The Spearman's rank correlation coefficient of 1.00 indicates a perfect linear correlation between the two groups. With the p-value of 0.00 at 95% significance level is more than the significance, [alpha] = 0.05, it suggests that there is significant relationship between the ranking of the factors under both the green and traditional building projects. There is strong agreement on the rankings of the impact by the labour related factors affecting project schedule as the influence might be comparable under the two types of projects.

3.2.7. Equipment and material related factors

As seen in Table 4, both traditional and green building projects have ranked factor EM7 as the highest most severe factor which may cause a project schedule delay under this category. Imported materials are long lead items which require a great number of weeks or months to be delivered on site. As such, any technical hitch on the delivery of imported materials especially when it concerns the critical activities in a schedule would cause adverse impact on the project leading to a delay. With reference to Table 4, majority of the factors have mean score less than 4.0 which implies that equipment and material related factors have relatively less impact on project schedule as compared to other categories. This might be due to the fact that equipment and material related factors can be better controlled and predicted in contrast with other categories.

The Spearman's rank correlation coefficient of 0.714 indicates a strong correlation between the two groups. As, the p-value of 0.090 at 95% significance level is more than the significance, [alpha] = 0.05, this indicates that there is insignificant relationship and agreement on the ranking of the factors between the two groups.

Disagreement on the rankings of the equipment and material related factors is observed between traditional and green building projects as this might be due to the fact that green technologies are usually imported from overseas. Therefore, the availability and delivery of these technologies is of higher importance (2nd in rank) than traditional building projects (3rd in rank). Low level of equipment-operator skill is ranked forth under green building projects; while it is sixth in rank under traditional building projects. It is attributable to the reason that green building construction projects require extensive knowledge and experience to incorporate the green technologies into the building design and during construction. As such, higher emphasis is place on the skill of the operator to construct and integrate the green technologies with the other building systems.

3.2.8. External related factors

Factor E6 is first in the rank with mean 4.40 and 4.70 for traditional and green building projects respectively. The high mean scores of factor E6 which are around 4.5 for both groups imply that any impediment in obtaining permits from political units/body of official will likely place the project to experience a project schedule delay. The ranking of factors between the two groups are relatively similar expect for the third and fourth ranked factors.

The Spearman's rank correlation coefficient of 0.943 indicates a strong correlation between the two groups. As, the p-value of 0.005 at 95% significance level is less than the significance, [alpha] = 0.05, this suggest that there is ample agreement and significant relationship on the ranking of the factors between the two groups.

It can be observed that there is agreement on the rankings of impact of the external related factors for both green and traditional projects. This might be because external factors are more unpredictable and it is hard to gauge whether there might be any difference on the degree of impact on the project schedule for different types of project. Therefore, it is assumed that the level of effect is comparative for traditional and green building projects.

3.2.9. Rank for all factors

The top 10 most significant delay factors for traditional building projects as identified in the survey were in sequence of CS3, P4, CL1, P3, DT1, CS2, CL4, CS5, E6, and CO3. Under green building projects, the 10 most significant delay factors are CL1, P3, CO3, CS5, P4, CL4, CS3, DT2, CS2, and DT1.

The Spearman's rank correlation coefficient value of 0.913 indicates a strong correlation between the two groups. As, the significance value = 0.000 at 95% significance level is less than the significance, [alpha] = 0.05, this suggest that there is ample agreement and significant relationship on the ranking of the factors between the two groups.

The common top three most important factors which have the greatest effect on project schedule delay for both green and traditional building projects are (1) Speed of decision making by client, (2) Speed of decision making involving all project teams, and (3) Communication/ coordination between key parties.

The speed of decision making by client was ranked first under traditional building projects, and third under green building construction projects. The speed of decision by client is considered one of the most significant factors as key decisions are ultimately made by the client. Any delay in decision making from the client, especially when the decisions have a strong impact on activities which lie on the critical path, it will impinge on the project progress and schedule.

Speed of decision making involving all project teams was ranked second for traditional building projects, and third under green building projects. It is essential that effective decisions should be taken at the right time. To achieve a successful project, the flow of information between all project team members should be systematic and timely, addressing to the appropriate personnel. In addition, key decision makers should be clearly identified to warrant effective decision making.

Communication and coordination between key parties was identified as another major factor by the respondents. Under green building projects, it was ranked second, while it was fifth in rank under traditional building projects. From the study done by Chalabi and Camp (1984), it is learnt that inadequate communication between project team members was a critical factor causing delays, which impede project progress leading to problems in the project coordination and schedule. Communication and coordination between key parties have a greater effect on schedule delay in green building projects due to the fact that green building construction projects requires a more holistic and integrated approach as the design process is more complex and much of the design phases overlap with the construction phases (Glavinich 2008). As such, green building projects requires more effort in communicating amongst the various team members (Kibert 2008).

In Table 4, the mean scores of each factor category were computed by taking an average of the mean scores of all the factors under the category. After which, the mean scores for each category are ranked.

The Spearman's rank correlation coefficient of 0.976 signifies a strong correlation between traditional and green building projects. As, the p-value of 0.000 at 95% significance level is less than the significance, [alpha] = 0.05, this suggest that there is strong agreement and significant relationship on the ranking of the factors between the two groups.

As seen from Table 4, there is substantial similarity between the top 3 factor categories which are deemed to have the highest impact on project schedule delay for both traditional and green building projects. The top 3 factor categories having the greatest influence on project schedule delay include (1) Client related factor, (2) Consultant related factor, and (3) Design team related factor.

Client, consultants and design team related factors were regarded to have the greatest impact on project schedule delay as it was agreed by most respondents that the planning and feasibility stage together with design stage were the two most important stages that determined the project schedule performance of the project. This was due to the fact that if the two stages were well planned and prepared, the design documents, such as drawings and specifications would be more complete and encompass all the requirements of client. As such, conflicts and changes can be prevented thus making it possible for the project to complete on time or ahead of as planned schedule (Al-Momani 2000). In accordance, without progress payment paid on time to contractors by the client, it vitiated the contractors' competency to finance the work and clients should minimize variations to ward off delays (Assaf et al. 1995).

3.3. Solutions for improving green building project schedule performance

The survey inquired about the respondents' sentiment in identifying possible recommendations to enhance green building construction project schedule performance. A total of 14 possible solutions were listed in the survey as shown in Table 5 and respondents selected top 5 solutions. The findings from the survey can be used to identify areas and aspects that should first be focused in order to reduce and prevent the factors causing delay of green building construction projects. Table 5 depicts ranking of the solutions based on the frequency of top 5 selected recommendations by the respondents.

Based on the result, the top 3 ranked solutions are discussed as follows:

--Ensure that the actual construction schedule and resources are seriously monitored and reviewed so that the performance is in line with as planned to avoid chances of cost overrun and disputes. Project managers should check that the green building construction planning and scheduling are in perpetual processes during construction and the schedule plans correspond with the time to develop the work and resources to prevent cost overrun and disputes (Assaf et al. 1995). To ensure that the project schedule and resources are constantly monitored and reviewed, owners may deploy certain tools and techniques for schedule control. A schedule control system may be set up to define the procedures when changes occur in the project schedule, and performance measurements should be carried out to assess the degree of variations that took place (Project Management Institute 2004).

--Check for mistakes and discrepancies in design documents to avoid redoing of designs and drawing before submission for approval to avoid variations or necessary corrections. When mistakes and discrepancies are discovered in design documents, redoing of designs and drawing requires extra time beyond the as-planned schedule to make the necessary changes (Assaf et al. 1995) and it will more often than not lead to poor time performance (Chan, Kumaraswamy 1996). When these mistakes and discrepancies are detected especially during the construction stage, variations leading to rework may take place thus giving rise to redundant work with additional cost pumped in to make the corrections.

--Alternative procurement method should be analysed to ensure it meets the project requirements and complexity. Every procurement method has a different course of project development and involves different relationships between all the project team members (Nofera, Korkmaz 2010). As such, clients should analyse the project characteristics with care to select the appropriate procurement method as misinterpretation of project characteristics would probably lead to poor project performance and resulting in cost growth (Council 2003). Due to the higher complexity of technical systems used in green building construction projects, the projects requires high levels of interdependency, communications and close partnerships with all the project participants during design stages (Kibert 2008; Magent et al. 2009). In addition, research had also shown that early involvement of owners would enable green building construction projects to achieve its green objectives at lower cost (Beheiry et al. 2006; Lapinski et al. 2006). Accordingly, it is vital to analyse alternative procurement methods to achieve better green building construction project performance.

3.4. Limitations

One of the limitations of the analyses performed above was the small sample size. With a higher response rate, it would be able to project a more accurate industrial perspective with regards to the current green construction schedule performance in comparison with traditional building construction projects. In addition, the analyses were performed based on consultants' and contractors' point of view as the client/developers of past green construction projects declined to respond to the research survey.

Conclusions and recommendations

While Singapore has earned recognition for its efforts in promoting a green built environment, the Building and Construction Authority (BCA) decided to turn upward its goal of greening, aiming to have at least 80% of Singapore's buildings Green Mark certified by 2030. Since all new building construction projects in Singapore are obliged to comply with Green Mark Scheme standards, it is therefore essential to look into how green building construction project performance can be managed more effectively.

The objectives of this study were: (1) investigate the degree of project delay in comparison between traditional and green projects; (2) analyze the causal factors of delay for both green and traditional projects; and (3) to discuss the possible solutions for the delay problems of green projects. The analysis on the survey results established that about 16% of the traditional building projects were delayed while about 32% of the green building projects were completed behind schedule. Furthermore, the top 5 critical factors that caused delay in green building projects were reported as (1) speed of decision making by client; (2) speed of decision making involving all project teams; (3) communication/coordination between key parties; (4) level of experience of consultants; and (5) difficulties in financing project by contractors.

The delay statistics in this study offers a benchmark for the industry to gauge the overall time duration required by green building construction projects as compared to traditional building projects. Similarly, Clients should take into consideration the additional time when setting out the overall project schedule for green building projects. In addition, the main factors that had significant impact on green building projects time performance in this research bring forth a focal point for project managers to enhance its performance for the project.

For future studies, construction time prediction models can be developed for green building construction projects of which the types can include residential, commercial, and industrial projects. In addition, assessment and comparison of schedule performance between green and traditional building construction projects can be done to set up a norm that can be used at the planning stage of green construction. Finally, it is also recommended to establish entire processes of project planning and feasibility studies for green projects as the processes directly affect schedule performance of green building construction projects.

doi: 10.3846/20294913.2013.798596

Received 07 September 2011; accepted 23 February 2013

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Bon Gang HWANG (a), Lay Peng LEONG (b)

(a) Department of Building, National University of Singapore, Singapore

(b) Department of Cost Control, EC Harris Singapore Pte Ltd, Singapore

Corresponding author Bon Gang Hwang B. G. Hwang E-mail: bdghbg@nus.edu.sg

Bon Gang HWANG (Dr) has been working as an Assistant Professor in the Department of Building at National University of Singapore Since 2008. He has several years of experience in the construction industry, working with Samsung Engineering & Construction Company, Korea, and Construction Industry Institute, USA. In his doctoral research, he specialized in developing industry-specific performance indicators and measurement /analysis/reporting systems. He has over 50 publications including journal papers, conference papers, and in the areas listed. His current research interests are in the areas of sustainable construction project management, performance assessment and improvement, rework identification and analysis, and risk management.

Lay Peng LEONG (Ms) graduated from the National University of Singapore in 2011 in Project and Facilities Management. She has been with EC Harris Singapore Pte Ltd, Singapore as an Cost Control Executive since 2011.

Table 1. Factors causing project schedule delays

                                                 Authors

               List of Factors                 Male (1988)

Project        Project delivery methods             V
related        Project cost
factors        Speed of decision making             V
                 involving all project teams
               Communication/coordination           V
                 between key parties
               Disputes/conflicts between
                 key parties

Client         Speed of decision making
related          by client
factors        Delay in progress payment
                 by client
               Client's level of experience         V
                 in the construction
                 industry
               Client initiated variation           V
                 of works

Design team    Mistakes and delay in                V
related          producing design
factors          documents
               Level of design team                 V
                 experience
               Complexity in project
                 design
               Misunderstanding of                  V
                 client's requirements
                 by design team

Consultant     Delay in performing
related          inspection and testing
factors        Delay in approving major
                 changes in the scope
                 of works
               Time for reviewing and
                 approval of design
                 documents by consultants
               Conflict between consultants
                 and design engineers
               Level of experience of
                 consultants

Contractor     Poor site management and             V
related          supervision
factors        Contractor's deficiencies in
                 planning and updating
                 schedule plans
               Difficulties in financing
                 project by contractors
               Construction methods
                 implemented by contractors
               Rework due to defects during
                 construction

Labor          Shortage of labor
related        Low labor productivity
factors        Unskilled labor

Equipment/     Equipment breakdown
material       Unskilled operators
related        Low productivity and
factors          efficiency of equipment
               Lack of high technology              V
                 mechanical equipment
               Availability of material
               Changes in materials
                 during construction
               Imported materials

External       Unforeseen ground                    V
factors          conditions
               Unfavourable weather
                 condition on
                 construction activities
               Accidents during
                 construction
               Changes in government
                 regulations and law
               Delay in performing final,
                 inspection and
                 certification by
                 third party
               Delay in obtaining permits           V
                 from political units/body
                 of officials

                                                  Authors

               List of Factors                 Mansfield et
                                                al. (1994)

Project        Project delivery methods
related        Project cost                          V
factors        Speed of decision making
                 involving all project teams
               Communication/coordination            V
                 between key parties
               Disputes/conflicts between
                 key parties

Client         Speed of decision making
related          by client
factors        Delay in progress payment
                 by client
               Client's level of experience
                 in the construction
                 industry
               Client initiated variation
                 of works

Design team    Mistakes and delay in                 V
related          producing design
factors          documents
               Level of design team
                 experience
               Complexity in project
                 design
               Misunderstanding of
                 client's requirements
                 by design team

Consultant     Delay in performing                   V
related          inspection and testing
factors        Delay in approving major              V
                 changes in the scope
                 of works
               Time for reviewing and
                 approval of design
                 documents by consultants
               Conflict between consultants
                 and design engineers
               Level of experience of
                 consultants

Contractor     Poor site management and
related          supervision
factors        Contractor's deficiencies in
                 planning and updating
                 schedule plans
               Difficulties in financing             V
                 project by contractors
               Construction methods                  V
                 implemented by contractors
               Rework due to defects during          V
                 construction

Labor          Shortage of labor
related        Low labor productivity
factors        Unskilled labor

Equipment/     Equipment breakdown
material       Unskilled operators
related        Low productivity and
factors          efficiency of equipment
               Lack of high technology
                 mechanical equipment
               Availability of material              V
               Changes in materials
                 during construction
               Imported materials                    V

External       Unforeseen ground                     V
factors          conditions
               Unfavourable weather                  V
                 condition on
                 construction activities
               Accidents during
                 construction
               Changes in government
                 regulations and law
               Delay in performing final,
                 inspection and
                 certification by
                 third party
               Delay in obtaining permits
                 from political units/body
                 of officials

                                                    Authors

               List of Factors                 Chan, Kumaraswamy
                                                     (1996)

Project        Project delivery methods
related        Project cost                            V
factors        Speed of decision making                V
                 involving all project teams
               Communication/coordination              V
                 between key parties
               Disputes/conflicts between              V
                 key parties

Client         Speed of decision making
related          by client
factors        Delay in progress payment
                 by client
               Client's level of experience
                 in the construction
                 industry
               Client initiated variation              V
                 of works

Design team    Mistakes and delay in                   V
related          producing design
factors          documents
               Level of design team                    V
                 experience
               Complexity in project                   V
                 design
               Misunderstanding of
                 client's requirements
                 by design team

Consultant     Delay in performing                     V
related          inspection and testing
factors        Delay in approving major
                 changes in the scope
                 of works
               Time for reviewing and                  V
                 approval of design
                 documents by consultants
               Conflict between consultants
                 and design engineers
               Level of experience of
                 consultants

Contractor     Poor site management and                V
related          supervision
factors        Contractor's deficiencies in            V
                 planning and updating
                 schedule plans
               Difficulties in financing
                 project by contractors
               Construction methods
                 implemented by contractors
               Rework due to defects during
                 construction

Labor          Shortage of labor                       V
related        Low labor productivity                  V
factors        Unskilled labor                         V

Equipment/     Equipment breakdown                     V
material       Unskilled operators
related        Low productivity and                    V
factors          efficiency of equipment
               Lack of high technology
                 mechanical equipment
               Availability of material                V
               Changes in materials                    V
                 during construction
               Imported materials

External       Unforeseen ground                       V
factors          conditions
               Unfavourable weather
                 condition on
                 construction activities
               Accidents during
                 construction
               Changes in government
                 regulations and law
               Delay in performing final,
                 inspection and
                 certification by
                 third party
               Delay in obtaining permits
                 from political units/body
                 of officials

                                                   Authors

               List of Factors                 Majid, McCaffer
                                                    (1998)

Project        Project delivery methods
related        Project cost
factors        Speed of decision making
                 involving all project teams
               Communication/coordination
                 between key parties
               Disputes/conflicts between
                 key parties

Client         Speed of decision making
related          by client
factors        Delay in progress payment              V
                 by client
               Client's level of experience           V
                 in the construction
                 industry
               Client initiated variation
                 of works

Design team    Mistakes and delay in
related          producing design
factors          documents
               Level of design team
                 experience
               Complexity in project
                 design
               Misunderstanding of
                 client's requirements
                 by design team

Consultant     Delay in performing
related          inspection and testing
factors        Delay in approving major
                 changes in the scope
                 of works
               Time for reviewing and
                 approval of design
                 documents by consultants
               Conflict between consultants
                 and design engineers
               Level of experience of
                 consultants

Contractor     Poor site management and
related          supervision
factors        Contractor's deficiencies in
                 planning and updating
                 schedule plans
               Difficulties in financing
                 project by contractors
               Construction methods
                 implemented by contractors
               Rework due to defects during
                 construction

Labor          Shortage of labor
related        Low labor productivity
factors        Unskilled labor                        V

Equipment/     Equipment breakdown                    V
material       Unskilled operators
related        Low productivity and
factors          efficiency of equipment
               Lack of high technology
                 mechanical equipment
               Availability of material
               Changes in materials
                 during construction
               Imported materials

External       Unforeseen ground
factors          conditions
               Unfavourable weather
                 condition on
                 construction activities
               Accidents during
                 construction
               Changes in government
                 regulations and law
               Delay in performing final,
                 inspection and
                 certification by
                 third party
               Delay in obtaining permits
                 from political units/body
                 of officials

                                                  Authors

               List of Factors                 Assaf et. al
                                                  (2006)

Project        Project delivery methods              V
related        Project cost
factors        Speed of decision making
                 involving all project teams
               Communication/coordination
                 between key parties
               Disputes/conflicts between            V
                 key parties

Client         Speed of decision making              V
related          by client
factors        Delay in progress payment             V
                 by client
               Client's level of experience
                 in the construction
                 industry
               Client initiated variation            V
                 of works

Design team    Mistakes and delay in                 V
related          producing design
factors          documents
               Level of design team                  V
                 experience
               Complexity in project                 V
                 design
               Misunderstanding of                   V
                 client's requirements
                 by design team

Consultant     Delay in performing                   V
related          inspection and testing
factors        Delay in approving major              V
                 changes in the scope
                 of works
               Time for reviewing and                V
                 approval of design
                 documents by consultants
               Conflict between consultants          V
                 and design engineers
               Level of experience of                V
                 consultants

Contractor     Poor site management and              V
related          supervision
factors        Contractor's deficiencies in          V
                 planning and updating
                 schedule plans
               Difficulties in financing             V
                 project by contractors
               Construction methods                  V
                 implemented by contractors
               Rework due to defects during          V
                 construction

Labor          Shortage of labor                     V
related        Low labor productivity                V
factors        Unskilled labor

Equipment/     Equipment breakdown                   V
material       Unskilled operators                   V
related        Low productivity and                  V
factors          efficiency of equipment
               Lack of high technology               V
                 mechanical equipment
               Availability of material              V
               Changes in materials                  V
                 during construction
               Imported materials

External       Unforeseen ground                     V
factors          conditions
               Unfavourable weather                  V
                 condition on
                 construction activities
               Accidents during                      V
                 construction
               Changes in government                 V
                 regulations and law
               Delay in performing final,            V
                 inspection and
                 certification by
                 third party
               Delay in obtaining permits            V
                 from political units/body
                 of officials

                                                  Authors

               List of Factors                  Alaghbari
                                               et al. (2007)

Project        Project delivery methods
related        Project cost
factors        Speed of decision making
                 involving all project teams
               Communication/coordination
                 between key parties
               Disputes/conflicts between
                 key parties

Client         Speed of decision making
related          by client
factors        Delay in progress payment
                 by client
               Client's level of experience
                 in the construction
                 industry
               Client initiated variation
                 of works

Design team    Mistakes and delay in
related          producing design
factors          documents
               Level of design team
                 experience
               Complexity in project
                 design
               Misunderstanding of
                 client's requirements
                 by design team

Consultant     Delay in performing
related          inspection and testing
factors        Delay in approving major
                 changes in the scope
                 of works
               Time for reviewing and
                 approval of design
                 documents by consultants
               Conflict between consultants
                 and design engineers
               Level of experience of                V
                 consultants

Contractor     Poor site management and
related          supervision
factors        Contractor's deficiencies in
                 planning and updating
                 schedule plans
               Difficulties in financing             V
                 project by contractors
               Construction methods
                 implemented by contractors
               Rework due to defects during          V
                 construction

Labor          Shortage of labor
related        Low labor productivity
factors        Unskilled labor                       V

Equipment/     Equipment breakdown
material       Unskilled operators
related        Low productivity and
factors          efficiency of equipment
               Lack of high technology
                 mechanical equipment
               Availability of material              V
               Changes in materials
                 during construction
               Imported materials

External       Unforeseen ground
factors          conditions
               Unfavourable weather
                 condition on
                 construction activities
               Accidents during
                 construction
               Changes in government                 V
                 regulations and law
               Delay in performing final,
                 inspection and
                 certification by
                 third party
               Delay in obtaining permits
                 from political units/body
                 of officials

                                                  Authors

               List of Factors                 El-Razek et
                                                al. (2008)

Project        Project delivery methods
related        Project cost                          V
factors        Speed of decision making
                 involving all project teams
               Communication/coordination            V
                 between key parties
               Disputes/conflicts between
                 key parties

Client         Speed of decision making              V
related          by client
factors        Delay in progress payment             V
                 by client
               Client's level of experience
                 in the construction
                 industry
               Client initiated variation            V
                 of works

Design team    Mistakes and delay in                 V
related          producing design
factors          documents
               Level of design team
                 experience
               Complexity in project
                 design
               Misunderstanding of
                 client's requirements
                 by design team

Consultant     Delay in performing                   V
related          inspection and testing
factors        Delay in approving major              V
                 changes in the scope
                 of works
               Time for reviewing and
                 approval of design
                 documents by consultants
               Conflict between consultants
                 and design engineers
               Level of experience of
                 consultants

Contractor     Poor site management and
related          supervision
factors        Contractor's deficiencies in          V
                 planning and updating
                 schedule plans
               Difficulties in financing
                 project by contractors
               Construction methods
                 implemented by contractors
               Rework due to defects during          V
                 construction

Labor          Shortage of labor
related        Low labor productivity                V
factors        Unskilled labor

Equipment/     Equipment breakdown
material       Unskilled operators                   V
related        Low productivity and                  V
factors          efficiency of equipment
               Lack of high technology
                 mechanical equipment
               Availability of material              V
               Changes in materials                  V
                 during construction
               Imported materials

External       Unforeseen ground                     V
factors          conditions
               Unfavourable weather                  V
                 condition on
                 construction activities
               Accidents during                      V
                 construction
               Changes in government
                 regulations and law
               Delay in performing final,
                 inspection and
                 certification by
                 third party
               Delay in obtaining permits            V
                 from political units/body
                 of officials

Table 2. Profile of companies and respondents

                                            Years of experience

               Characteristics        1 to 2 years         2 to 3 years

                                        C.I         G         C.I

Company        Construction              0          2          0
               Consulting                0          0          0
               Development               0          0          0
               Quantity Surveying        0          0          0
               Total                  0 (0%)    2 (6.67%)    0 (0%)

Respondent     Project Manager/          0          3          0
               Construction Manager
               Project Director/         0          0          0
               Higher Management
               Project Personnel         0          0          0
               Total                  0 (0%)     3 (10%)     0 (0%)

                                         Years of experience

               Characteristics        2 to 3 years  3 to 4 years

                                           G           C.I

Company        Construction                3            0
               Consulting                  0            0
               Development                 0            0
               Quantity Surveying          0            0
               Total                    3 (10%)         0%

Respondent     Project Manager/            3            0
               Construction Manager
               Project Director/           1            0
               Higher Management
               Project Personnel           1            1
               Total                  5 (16.67%)    1 (3.33%)

                                       Years of experience

               Characteristics        3 to 4 years  >4 years

                                           G            C.I

Company        Construction                4            18
               Consulting                  1             5
               Development                 1             3
               Quantity Surveying          0             4
               Total                    6 (20%)      30 (100%)

Respondent     Project Manager/            5            18
               Construction Manager
               Project Director/           3             4
               Higher Management
               Project Personnel           2             7
               Total                  10 (33.33%)   29 (96.67%)

                                       Years of experience

                                      >4 years      Total
               Characteristics                      (N = 30)

                                           G

Company        Construction                9        18 (60%)
               Consulting                  4        5 (16.67%)
               Development                 2        3 (10%)
               Quantity Surveying          4        4 (13.33%)
               Total                  20 (63.33%)   30 (100%)

Respondent     Project Manager/            7        18 (60%)
               Construction Manager
               Project Director/           0        4 (13.33%)
               Higher Management
               Project Personnel           5        8 (26.67%)
               Total                   12 (40%)     30 (100%)

C.I refers to years of experience in construction industry;

G refers to years of experience in green building construction;

Higher Management includes Executive president, Project
Director, General Manager and Managing Director;

Project Personnel includes Project Engineers,
Construction Engineers, and Quantity Surveyors.

Table 3. Project delay: traditional vs. green building projects

Characteristics                            (a) No. of     (b) No. of
                                           Traditional     Projects
                                            Projects       Delayed
                                            Performed      among (a)

Project Type      Commercial                    48            12
                  Residential                   91             9
                  Educational                   81            14

Project Nature    New Construction             184            32
                  Addition & Alteration         36             3

Project Size      Less than $5M                 32             4
                  $5M to less than $10M         6              0
                  $10M to less than $20M        35             5
                  $20M to less than $30M        33             0
                  $30M to less than $40M        15             1
                  $40M to less than $50M        27             4
                  $50M and Above                72            21

All Projects                                   220            35

Characteristics                            Percentage    (c) No. of
                                             Delayed       Green
                                                          Projects
                                                          Performed

Project Type      Commercial                 25.00%          28
                  Residential                 9.89%          21
                  Educational                17.28%          47

Project Nature    New Construction           17.39%          93
                  Addition & Alteration       8.33%           3

Project Size      Less than $5M              12.50%           3
                  $5M to less than $10M       0.00%           8
                  $10M to less than $20M     14.29%           6
                  $20M to less than $30M      0.00%          13
                  $30M to less than $40M      6.67%          16
                  $40M to less than $50M     14.81%          18
                  $50M and Above             29.17%          32

All Projects                                 15.91%          96

Characteristics                            (d) No. of    Percentage
                                            Projects       Delayed
                                            Delayed
                                            among (c)

Project Type      Commercial                   16          57.14%
                  Residential                   0           0.00%
                  Educational                  15          31.91%

Project Nature    New Construction             31          33.33%
                  Addition & Alteration         0           0.00%

Project Size      Less than $5M                 1          33.33%
                  $5M to less than $10M         2          25.00%
                  $10M to less than $20M        0           0.00%
                  $20M to less than $30M        3          23.08%
                  $30M to less than $40M        5          31.25%
                  $40M to less than $50M        7          38.89%
                  $50M and Above               13          40.63%

All Projects                                   31          32.29%

Table 4. Delay factors: traditional vs. green building projects

                                                             Within
                                                            Categories

                    Factors                                 Traditional

                                                               Mean

Project       P1    Project delivery methods                   4.03
related       P2    Project cost                               4.03
factors       P3    Speed of decision making                   4.53
                      involving all project teams
              P4    Communication/coordination                 4.57
                      between key parties
              P5    Disputes/conflicts between                 3.17
                      key parties

Client        CL1   Speed of decision making by client         4.53
related       CL2   Delay in progress payment by client        4.07
factors       CL3   Client's level of experience in            4.43
                      the construction industry
              CL4   Client initiated variation                 3.80
                      of works

Design        DT1   Mistakes and delay in producing            4.47
team                  design documents
related       DT2   Level of design team experience            4.03
factors       DT3   Complexity in project design               4.13
              DT4   Misunderstanding of client's               4.00
                      requirements by design team

Consultant    CS1   Delay in performing inspection             4.13
related               and testing
factors       CS2   Delay in approving major changes           4.47
                      in the scope of works
              CS3   Time for reviewing and approval of         4.60
                      design documents by consultants
              CS4   Conflict between consultants and           4.17
                      design engineers
              CS5   Level of experience of consultants         4.43

Contractor    CO1   Poor site management and supervision       4.20
related       CO2   Contractor's deficiencies in planning      4.20
factors               and updating schedule plans
              CO3   Difficulties in financing project          4.40
                      by contractors
              CO4   Construction methods implemented           3.93
                      by contractors
              CO5   Rework due to defects during               3.27
                      construction

Labor         L1    Shortage of labor                          4.13
related       L2    Low labor productivity                     3.63
factors       L3    Unskilled labor                            3.50

Equipment/    EM1   Equipment breakdown                        3.40
material      EM2   Unskilled operators                        3.27
related       EM3   Low productivity and efficiency            3.57
factors               of equipment
              EM4   Lack of high technology                    3.60
                      mechanical equipment
              EM5   Availability of material                   3.63
              EM6   Changes in materials during                3.83
                      construction
              EM7   Imported materials                         4.03

External      E1    Unforeseen ground conditions               3.67
factors       E2    Unfavourable weather condition             3.50
                      on construction activities
              E3    Accidents during construction              3.97
              E4    Changes in government regulations          3.73
                      and law
              E5    Delay in performing final inspection       3.80
                      and certification by third party
              E6    Delay in obtaining permits from            4.40
                      political units/body of officials

                                Within Categories

                   Traditional     Green        Spearman
                                                  Rank
                      Rank      Mean    Rank   Correlation   P-value
                                               Coefficient

Project       P1        3       4.30     3        0.895       0.040
related       P2        4       4.30     4
factors       P3        2       4.77     1
              P4        1       4.70     2
              P5        5       3.47     5

Client        CL1       1       5.00     1        1.000       0.000
related       CL2       3       4.17     3
factors       CL3       2       4.67     2
              CL4       4       4.13     4

Design        DT1       1       4.27     3        0.400       0.600
team          DT2       3       4.63     1
related       DT3       2       4.53     2
factors       DT4       4       4.17     4

Consultant    CS1       5       4.00     5        0.700       0.188
related       CS2       2       4.57     3
factors       CS3       1       4.63     2
              CS4       4       4.43     4
              CS5       3       4.70     1

Contractor    CO1       3       4.53     2        0.975       0.005
related       CO2       2       4.47     3
factors       CO3       1       4.70     1
              CO4       4       4.27     4
              CO5       5       3.43     5

Labor         L1        1       4.10     1        1.000       0.000
related       L2        2       3.67     2
factors       L3        3       3.57     3

Equipment/    EM1       6       3.37     7        0.685       0.090
material      EM2       7       3.53     4
related       EM3       5       3.50     5
factors       EM4       4       3.37     6
              EM5       3       4.17     2
              EM6       2       4.07     3
              EM7       1       4.33     1

External      E1        5       3.53     5        0.943       0.095
factors       E2        6       3.37     6
              E3        2       4.13     2
              E4        4       3.90     3
              E5        3       3.87     4
              E6        1       4.47     1

                              Cross Categories

                    Traditional     Green     Spearman
                                                Rank
                     Overall       Overall   Correlation
                       Rank          Rank    Coefficient   P-value

Project       P1        18            16
related       P2        18            16
factors       P3         3             2
              P4         2             3
              P5        39            35

Client        CL1        3             1
related       CL2       17            20
factors       CL3        7             6
              CL4       26            23

Design        DT1        5            18
team          DT2       18             7
related       DT3       14            10
factors       DT4       22            20

Consultant    CS1       14            27
related       CS2        5             9
factors       CS3        1             7
              CS4       13            14
              CS5        7             3

Contractor    CO1       11            10         0.913       0.000
related       CO2       11            12
factors       CO3        9             3
              CO4       24            18
              CO5       37            36

Labor         L1        14            25
related       L2        30            30
factors       L3        34            31

Equipment/    EM1       36            37
material      EM2       37            32
related       EM3       33            34
factors       EM4       32            37
              EM5       30            20
              EM6       25            26
              EM7       18            15

External      E1        29            32
factors       E2        34            37
              E3        23            23
              E4        28            28
              E5        26            29
              E6         9            12

Table 5. Solutions for improving green building project
schedule performance

Solutions for Schedule            Frequency of    Percentage   Rank
Improvement of Green             Top 5 Selected
Buildings

Ensure that the actual                  23           76.67%      1
construction schedule and
resources are seriously
monitored and reviewed so
that the performance is in
line with as planned to
avoid the chances of cost
overrun and disputes

Check for mistakes and                  19           63.33%      2
discrepancies in design
documents to avoid redoing
of designs and drawing
before submission for
approval to avoid
variations or
necessary corrections

Alternative procurement                 16           53.33%      3
method should be analysed
to ensure it meets the
project requirements
and complexity

Ensure that design                      14           46.67%      4
documents are produced
on time

Ensure that there is                    14           46.67%      5
optimum number of labours
to be assigned for
individual activities
and motivate the workers
to increase productivity

Pay progress payment to the             12           40.00%      6
contractor timely to
facilitate the contractors'
ability to finance the work

To minimize variation                   11           36.67%      7
orders to avoid delays

Contractor should manage his            7            23.33%      8
financial resources and plan
cash flow by utilizing
progress payment

Avoid delay in when reviewing           6            20.00%      9
and approval of documents,
materials or others are needed

Ensure that contractor have             4            13.33%      10
the capability and the
resources for constructing
the project before awarding
the tender

Administrative and technical            4            13.33%      11
staff should be appointed as
soon as project is awarded to
facilitate the project is
completed within specified
time with the required
quality and estimated cost

Consultants should not delay            3            10.00%      12
the checking, reviewing and
approving of design documents
leading to a delay in
construction phase

Consultant should be flexible           3            10.00%      13
in evaluating contractors work
and balance between the
required quality with cost

Contractor should carry out             3            10.00%      14
a comprehensive economic
analysis and workable
financial plans