Presents a method based on a constrained optimization technique that determines the time of removal of scientific periodicals from the shelf of a library. A geometrical interpretation of the theoretical result is given, and a numerical example illustrates how the technique is applicable to real bibliographic data. (FM)

Analyzes the half-life of book use through analysis of over 10,000 regional and statewide interlibrary loan requests. Correcting for the growth of the literature, this study indicated that the half-lives of monographs may increase from lower to higher levels of the hierarchy in a library network. (CWM)

Reports the results of a study which examined the need for and use of both academic and professional materials in library collections for professional education. The measures used included proportions of materials in an existing business collection, and comparisons of patron use and obsolescence rates of academic and professional materials. (CLB)

Examines the distribution of use of items in a large information store and suggests that a simple exponential model describes the process of obsolescence more precisely. Three tables, four figures, and a 17-item reference list are included. (Author/JL)

A survey of 75 small academic libraries reveals that most hold reasonably current editions of four or five different general encyclopedias with considerable agreement on most popular titles. Encyclopedias are used primarily for ready reference and general introductions to research topics; new editions are purchased at least every five years. (EJS)

Determines book obsolescence rates for instructional departments within university by analyzing annual library's circulation and relating patterns of library use to curricular programs. Immediacy and intensity of peak usage, use dispersion, and commonality of use were used to develop acquisition priority weighting formula. Twenty-two sources and…

Seven articles on library reference services highlight reference obsolescence in academic libraries, major studies of unobtrusive reference tests, methods for evaluating reference desk performance, reference interview evaluation, problems of reference desk control, online searching by end users, and reference collection development in…