摘要：Objectives. We assessed the effect of social marketing incentives on dispositions toward retrofitting and retrofitting behavior among farmers whose tractors lacked rollover protective structures. Methods. From 2006 to 2007, we conducted a quasi–randomized controlled trial with 391 farm owners in New York and Pennsylvania surveyed before and after exposure to 1 of 3 tractor retrofitting incentive combinations. These combinations were offered in 3 trial regions; region 1 received rebates; region 2 received rebates, messages, and promotion and was considered the social marketing region; and region 3 received messages and promotion. A fourth region served as a control. Results. The social marketing region generated the greatest increases in readiness to retrofit, intentions to retrofit, and message recall. In addition, postintervention stage of change, intentions, attitudes, subjective norms, and perceived behavioral control levels were higher among farmers who had retrofitted tractors. Conclusions. Our results showed that a social marketing approach (financial incentives, tailored messages, and promotion) had the greatest influence on message recall, readiness to retrofit tractors, and intentions to retrofit tractors and that behavioral measures were fairly good predictors of tractor retrofitting behaviors. National Safety Council statistics show that farming has the highest fatality rate among US industries, 1 with rates roughly 8 times the national average. 2 Although state-to-state variation exists, 3 – 5 it is estimated that more than one third of farm deaths in this country are tractor-related. 6 Roughly half of tractor-related deaths result from overturns. 7 Overturn fatalities occur when tractors lacking a roll bar or cab turn over, crushing the operator. Certified roll bars or cabs, referred to as rollover protective structures (ROPSs), have been shown to dramatically reduce injuries and fatalities. 6 These devices limit the extent of the roll and hold the operator in a protective zone, provided seatbelts are used. In 1985, ROPSs became standard equipment on new tractors. 8 Before 1985, farmers frequently declined to purchase ROPSs to avoid the extra expense. Acquiring ROPSs for pre-1985 models entails locating, purchasing, and either self-installing or paying for installation. Despite efforts to reduce US overturn fatalities, the percentage of tractors with ROPSs (30%–50% at the time the study was conducted) and annual rates of overturn fatalities (7/100 000 tractors) have improved more slowly than in other developed nations. 7 Trends from 1960 to the late 1980s in Sweden (from 17 to 0.3 deaths/100 000 tractors), 9 Denmark (from 30 to 2 deaths/100 000 tractors), 9 West Germany (from 6.7 to 1.3 deaths/100 000 tractors), 10 and Australia (reduction of unprotected tractors from 24% to 7%) 11 have been more encouraging. The lack of progress in the United States is likely attributable to several barriers. Installing a ROPS can be expensive and time consuming. A ROPS typically costs $600 to $1500, and several telephone calls may be required to locate the appropriate model. 12 Lack of farmer interest has also been cited as a potential barrier. 13 Successful programs in other countries have addressed these barriers by providing financial assistance and legislating mandatory installation. However, resistance to regulation from US farmers makes other approaches necessary. 14 Recently, researchers have speculated that social marketing may be an effective means of increasing the percentage of ROPS-protected tractors. 6 Social marketing identifies a population's needs, values, and barriers to change and designs interventions that address them. This approach differs from traditional interventions because it appeals to existing values and norms rather than trying to change them. Although the literature contains reports on the impact of financial assistance and messages on behavior, 12 , 15 it lacks a scientific evaluation of which incentives or combination of incentives is most effective. No evaluation of the effect of social marketing on tractor retrofitting has been conducted. The goals of the New York State ROPS Rebate Program are to increase the proportion of ROPS-equipped tractors and to increase farmers’ readiness to retrofit. We previously described the program design,16 target population identification, 17 and identification of barriers to tractor retrofitting. 18 We also reported data from the rebate program's hotline, along with inspections of self-installed ROPSs. 19 – 21 Recently, we assessed the effect of retrofitting incentives and the overall efficacy of the rebate program.
