Database usage data from a random sample of ninety-eight public libraries and library systems in the United States and Canada reveal patterns of use. Library users at all sizes of public libraries tend to use research databases most frequently early in the week, at midday, and at times that correspond to the academic calendar (November in this six-month sample.) Peak usage varies with size of library, but a capacity of between one and ten simultaneous users will satisfy 99 percent of demand in every size of library. A questionnaire sent to these libraries revealed many other factors that might influence database use, including posting signs or preparing handouts, availability of remote login, and placement of a database on the library's homepage. Only the number of workstations, adjusted for population, was found to be statistically correlated with amount of use.
Public librarians often find themselves negotiating complex licensing agreements when selecting fee-based digital resources for their libraries. Resources that will be offered online through a library may be priced by vendors in a variety of ways. A popular pricing scheme for public libraries involves negotiating a price that depends on the number of users allowed online at any one time on any one database. This simultaneous (or concurrent) use pricing scheme allows libraries to keep costs down and pay only for the number of users likely to be needing a database at one time. The success of this pricing scheme depends on accurate estimates of how many simultaneous users should be supported. If too few are supported, users get frustrated by system "busy" signals; supporting too many simultaneous users results in unnecessarily expending scarce resources on higher fees.
Predicting likely numbers of simultaneous users is especially difficult when there is no history of prior usage. The library that is leasing a new product or offering online access for the first time must often guess about how much each database will be used. Usage data from other public libraries may, however, help similar libraries to predict levels and patterns of use. Other factors such as how many workstations are available in a library and whether or not the library allows remote access may also complicate this picture.
A two-phase study of public libraries helped identify patterns of database use, levels of simultaneous use, and what factors might influence this use. Online data captured from ninety-eight public libraries reveal (1) how many users are logged on simultaneously to selected online research databases and (2) the time of day, week, and month when users are searching the most. Examination of these data may help other libraries negotiate simultaneous usage licenses and estimate the number of workstations and ports required.
Usage data do not show, however, what each individual library is doing, if anything, to encourage use of databases. In a supplemental survey, each library for which usage data were gathered was asked about its specific environment for online access, and information was gathered about factors that may influence online use.
Review of the Literature
Historically, usage studies were used to predict an appropriate number of chairs to provide in the library or to adjust staffing schedules to correspond to peak times. Later studies helped libraries determine how many terminals were required for their new online catalogs. A 1983 report incorporated queuing models to recommend appropriate numbers of terminals for online catalogs. Turnstile counts have been used to optimize reference department staffing or pickup schedules for shelving. Turnstile counts show that peak usage periods in academic libraries correspond to the academic calendar and daily class schedules.
Patterns or levels of use from within a library may be different from remote use patterns. The New York Public Library Research Libraries compared patterns for remote usage of their OPAC with patterns of usage from within the libraries. They found that patterns for remote searching of the OPAC are distributed more evenly over each day and within each week than in-library searching, and a "large part of remote searching occurred when the Research Libraries were closed." In a call for better computerized monitoring of remote users, Peters discussed the widespread belief that remote users will likely follow "diurnal" usage patterns, but suggested that this may only be true in metropolitan areas "already noted for diurnally diffuse human behavior."
Data such as turnstile counts or other measures of amount of use are not sufficient to reveal why a particular resource is used. Townley and Murray found in a study of six southwestern academic libraries that database use did not fit a predictable pattern across libraries and databases. Database use is influenced by the length of time the database has been available (available more than one year results in heaviest use), limiting the forms of access to the database, the source of the database (locally loaded and Internet-based databases were preferred), and the availability of user instruction in the library.
Librarians' attitudes or factors such as convenience, accessibility of a database through menu screens, or the availability of training materials might be expected to influence the amount of use that any specific resource such as an online database receives. Tenopir and Ennis analyzed university reference librarians' attitudes toward electronic reference products and changes throughout the 1990s. Librarians reported that users prefer electronic reference products over print resources, both from within the library and through dial-up access. End-user online searching of commercial databases is now an integral part of library reference services and users have come to expect online access through their libraries.
Collection development and reference librarians now spend much of their time evaluating and selecting online resources, a task more complex than, but not unlike, traditional selection and collection building. Added to the traditional task of evaluating quality, content, coverage, and ease of use, is the need to select the best possible pricing options from among many alternatives and to negotiate online licensing agreements. The best pricing option will vary from library to library and, within a library, may be different for heavily used resources than for those used less often.
The information reported here is part of a larger study that examines patterns and factors of use for both academic and public libraries. This study demonstrates that, while the exact amount of use varies with the size and type of library, the usage patterns in academic and public libraries of all sizes are similar. Although libraries have their own unique situations, learning from other similar libraries may be the best way to estimate how many users will likely use a database and when that usage will occur. The present article updates, corrects, and expands on some of the data in these earlier reports. Usage data show how much online …