The traditional (or Alexandrian) model of the library is based upon the mistaken intuition that to be good a library must be vast and always growing."(1) Weeding of library collections, whether printed or electronic, whether by choice or compulsory, creates opportunities for criticism and growth. Where the literature suggests that starting a weeding project is close to last on a librarian's list, events beyond a librarian's control can force a weeding action. Space reallocations, time constraints, or e-provider policies imposes risks that threaten the attempt to maintain a viable collection. Sometimes the choice is voluntary; but if not explicitly defined as part of a formal collection policy, the rationale used can vary, and if the librarian is inexperienced, the methodology risks being incomplete or at worst, inaccurate. Although varied criteria exist to help determine what to weed, successful results depend on proper application. Considerations such as local historical interest or the ubiquitous nature of the content will impact decisions as much as typical variables such as physical condition, usage, or curricular integration. Additionally, within the disciplines that many engineering librarians support, the volatility of those subject disciplines can vary widely. Paying particular attention to engineering-related subject disciplines, this paper will outline historical motivations that drive weeding initiatives, describe varying methods previously employed, and propose if a systematic rationale for applying metrics to determine candidate materials as a function of discipline could be developed and successfully employed. By listing potential variables, suggesting which ones would be emphasized for particular collections, and contrasting their application in a manual versus an algorithmically applied routine, the paper will propose a best practice methodology.
