Developing a balanced and usable collection is an important aspect of library services. Academic library collections are built to meet specific research and information needs of the institution's academic programmes. The curriculum is the frame upon which the library collection is built. All programmes must be covered to facilitate effective teaching, learning, research, and community services. Collection analysis and evaluation are crucial to ensuring efficient, effective, and usable collections. Collection effectiveness is measured, according to Lumande and Ojedokun (2005), by the extent to which a library collection can facilitate research activities and how much students can rely on it for project and assignments. Pausch and Popp (1997) maintain that accountability, outcomes measurement, and assessment are the subject of discussions in higher education, and coupled with the fact that libraries collections consume large proportion of the budget, libraries must ensure that what is collected matches or meets the expressed needs and information expectation of the university communities. One of way of ensuring that such needs are met is through collection evaluation within the framework of the curriculum. Crowder (1997) defines curriculum as the courses or programmes of study offered by an educational institution. It includes all activities that students must complete to finish a programme of study and achieve learning goals. The curriculum is not a fixed product but a dynamic process that responds to changes both in the society and in the educational institution, the library should be positioned to effectively respond to curriculum changes.
Another reason for collection evaluation is accreditation by bodies such as the Nigerian Universities Commission (NUC), Nigerian Legal Council, Nigerian Medical and Dental Association, and others. This imposes more responsibilities on the library, which has to ensure that the collection reflects the requirements for accreditation. Wright (2005) views accreditation as the vehicle to monitor the quality of education.
Collection Evaluation Methods
Pastine (1996) identifies a number of methodologies in literature which have received some acceptance and use in academic and research libraries. Some methods rely on collecting qualitative or quantitative statistics (Credaro, 2001). Quantitative statistics involves variables such as the current number of items in the collection, number of items added or rate of growth and items available per student in comparisons to recommended lists or to similar library collections and the study of the age of the collection. Qualitative approaches include analysis of circulation and InterLibrary Lending (ILL) statistics and in-house use studies of materials. A user satisfaction survey which employs a questionnaire or survey is another technique. This method is sometimes followed up with telephone interviews (Silveria, 1996). Studies of the citations and bibliographies of customers' publications to find out if items cited are available in the collections is another method of collection evaluation and assessment of customer satisfaction (Pastine, 1996). Credaro (2001) has identifies three ways of evaluating a library collection: survey of user opinion, which is user centered (through questionnaire or interview); the conspectus approach which involves the use of subject descriptors; and the cumulative approach, which combines some of the first two methods of collection assessment. Credaro concludes that "the success of any method of assessment depends on how well it meets the goals of the evaluation." In evaluating multimedia resources, Lamb (2004) agrees that collection evaluation can centre on either the collection or the customer. He identifies three methods: collection mapping, circulation statistics and patron survey.
There are many benefits derivable from collection evaluation. Lamb (2004) submits that "collection evaluation helps librarians to review the strength and weaknesses of the entire...