Judging the Need for and Value of DDA in an Academic Research Library Setting

This article reports findings from a multiphase analysis of demand-driven acquisitions (DDA) within the academic research library setting. Evaluating local collections within the context of Trueswell's (1969) often-cited 80/20 Rule, phase one of this study illustrates the deficiencies of a just-in-case approach to building library collections. Following from this, phase two evaluates the viability of DDA as the just-in-time collection-building solution librarians have sought as an answer to low-use titles that plague most academic library collections. Supported by 16 months of data, this study scrutinizes the comparative value of DDA against traditionally acquired titles along two key dimensions-the subject-matter profile of purchases and their overall usage levels. Further, the concept of a utility as value paradigm, as well as a purchase-use equilibrium for library collections, provide a theoretical framework in which the relative value of DDA is assessed. From a content, or subject-matter, perspective, this study finds negligible deviation in those purchasing patterns associated with DDA when compared with traditionally-acquired materials. At the same time, DDA titles experience much higher levels of use and are, therefore, associated with markedly lower cost-per-use figures and greater overall value.