Interlibrary Loan Offices can supply documents for only a fraction of the lending requests received (i.e., requests for the loan of a book or photocopy of an article received from another library), despite sophisticated electronic verification/locating systems. Lending fill rates of 50 percent are common. As a consequence, an interlibrary loan request must be referred to several different libraries before being satisfied. This inefficiency significantly lengthens the time required to deliver a document to a patron. This study analyzes 7,587 failed OCLC interlibrary loan and copy requests to determine why the requests could not be supplied. It was found that loan requests most often fail because local policies prevent loan or the items were in use. Copy requests most often failed due to the requested volume of a serial not being owned.
Although significant technological improvements have been made to the interlibrary loan (ILL) process to speed receipt of requested materials, at least one study has observed that turnaround time for ILL transactions has varied little since 1979. (1) One reason cited for long turnaround times is the inability of a requesting library to locate potential lenders of materials accurately. Despite sophisticated electronic verification and locating systems, ILL offices can often fill only 50 percent of the lending requests received. Each of these unfilled requests must be referred again and again until satisfied. This inefficiency is a source of considerable delay in the ILL process.
Each time a request is referred, the total turnaround time of the request is measurably increased. Because multiple referrals add significantly to turnaround, one strategy to speed turnaround time is to request from as few institutions as possible. Identifying why libraries must refer 50 percent of their lending requests has been the subject of only a handful of recent research studies. Furthermore, previous studies have focused on failed book requests without examining the reasons serial requests fail. By identifying the reasons ILL and photocopy or copy requests are not filled, it may prove possible to reduce the probability of failure and, consequently, improve the turnaround time.
Several earlier studies have shown that ILL success rates (the proportion of all ILL borrowing requests successfully completed) are between 80 and 90 percent. (2) Each of these studies based success on the final transaction, ignoring the number of referrals a request may have required. This is particularly true of libraries using the OCLC ILL Subsystem as a primary means for sending requests. However, when success is limited to that of being the first library in the OCLC lender string, Dodson et al. found that only 57.1% of requests were completed. (3) Nearly 43% were not filled and were referred to the next potential lender. Gorin and Kanen found similar results: 52.6% for the first library, 21.4% for the second, and 16.4% for the third. (4)
Explanations as to why such a large proportion of OCLC requests must be referred, despite having accurate location information, are elusive. Robert B. Winger examined the book-lending requests of the University of Chicago's Joseph Regenstein Library. (5) Of approximately 8,061 book requests received, 55.5% (approximately 4,471) were not filled. Winger analyzed and grouped a sample of 347 of the unfilled book requests into five categories: not owned, 29.14% (volume or edition not owned, not owned as cited), no longer in collection, 14.28% (missing, lost, discarded, transferred), unavailable for lending, 49.43% (in use, at bindery, noncirculating), miscellaneous/policy, 6.27% (lent before to same reader, duplicate request, request cancelled), and no reason given, 0.50%.
A 1986 study of the Illinois Library and Information Network (ILLINET) examined failed ILL book borrowing (not lending) requests to determine reason for nonsupply. Again, copy requests were excluded from the study. …