摘要：Introduction: Primary access libraries serve as the foundation of the National Network of Libraries of Medicine (NN/LM) interlibrary loan (ILL) hierarchy, yet few published reports directly address the important role these libraries play in the ILL system. This may reflect the traditional view that small, primary access libraries are largely users of ILL, rather than important contributors to the effectiveness and efficiency of the national ILL system. Objective: This study was undertaken to test several commonly held beliefs regarding ILL system use by primary access libraries. Hypotheses: Three hypotheses were developed. H1: Colorado and Wyoming primary access libraries comply with the recommended ILL guideline of adhering to a hierarchical structure, emphasizing local borrowing. H2: The closures of two Colorado Council of Medical Librarians (CCML) primary access libraries in 1996 resulted in twenty-three Colorado primary access libraries' borrowing more from their state resource library in 1997. H3: The number of subscriptions held by Colorado and Wyoming primary access libraries is positively correlated with the number of items they loan and negatively correlated with the number of items they borrow. Methods: The hypotheses were tested using the 1992 and 1997 DOCLINE and OCLC data of fifty-four health sciences libraries, including fifty primary access libraries, two state resource libraries, and two general academic libraries in Colorado and Wyoming. The ILL data were obtained electronically and analyzed using Microsoft Word 98, Microsoft Excel 98, and JMP 3.2.2. Results: CCML primary access libraries comply with the recommended guideline to emphasize local borrowing by supplying each other with the majority of their ILLs, instead of overburdening libraries located at higher levels in the ILL hierarchy (H1). The closures of two CCML primary access libraries appear to have affected the entire ILL system, resulting in a greater volume of ILL activity for the state resource library and other DOCLINE libraries higher up in the ILL hierarchy and highlighting the contribution made by CCML primary access libraries (H2). CCML primary access libraries borrow and lend in amounts that are proportional to their collection size, rather than overtaxing libraries at higher levels in the ILL hierarchy with large numbers of requests (H3). Limitations: The main limitations of this study were the small sample size and the use of data collected for another purpose, the CCML ILL survey. Conclusions: The findings suggest that there is little evidence to support several commonly held beliefs regarding ILL system use by primary access libraries. In addition to validating the important contributions made by primary access libraries to the national ILL system, baseline data that can be used to benchmark current practice performance are provided.
