• Journal of the Korean Society for Library and Information Science
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• v.50 no.3
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• pp.429-453
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• 2016

This study analyzes circulation patterns of books with checkout transaction count by 11 subject areas, 5 positions, and 5 divisions with a Use Factor developed by Bonn in an Academic Library. 20% of the loan books occupies more than half of circulation and these are regarded as core collection. It proposes a 'Loan books 20/50 rule' that 20% core collection accounts for 50% of its circulation. It analyzes the proportion of core collection from the aspect of each subject area with a use factor, monthly change trend and loan period. It also defines 'book usage' considering checkout frequency of each title and loan period. Circulation patterns of core collection are compared and analyzed in terms of both checkout frequency and book usage. Core collection occupies about more than half of both total checkout transactions and total book usages and they all show a Power Law distribution.

• Journal of Korean Library and Information Science Society
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• v.48 no.2
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• pp.263-293
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• 2017

The purpose of this study is to analyze user behaviors of books in detail based on circulation data in an academic library. It analyzes circulation patterns of books for ten years from 2006 to 2015, which are surprisingly similar every year. Each pattern follows 'Loan books 20/50 rule' that 20% core collection occupies 50% of its circulation every year. This clarifies users' circulation patterns are highly consistent and very expectable. Also, using the cumulative distribution of book age, it defines the half-life of books and suggests the mathematical formula to measure it. Circulation patterns of the whole loan book and core collection for ten years are very different in terms of subjects, user groups, and divisions. This indicates that core collection plays a significant role in analyzing circulation statistics and usage patterns for the efficient collection development in the future.