Introduction

Interlibrary loan (ILL) in the state of Illinois is characterized by statewide partnerships and agreements for sharing local collections. Libraries borrow items from other libraries that they do not own and which are needed by their patrons. Analyzing ILL records is a very basic way to determine what libraries need, but do not own, or which are unavailable due to binding, theft, or are simply missing from the collection. These records can also show frequency of need, helping to answer the "buy or borrow" question for libraries. The Illinois Interlibrary Loan Assessment Project was initiated to review ILL records for 26 libraries in Illinois for which ILL data was made available for a one-year period, to determine the nature and scope of journal-article interlibrary lending and borrowing in the state.

The most basic review of ILL data for these 26 Illinois libraries can identify how many ILL transactions are filled by the 26 libraries, are filled by other libraries within the state, and are filled outside Illinois. Due to the partnerships established within the state, journal articles held in Illinois are more speedily supplied and are more cost-effective to borrow than those held outside of Illinois, which can cost two to three times as much as an in-state loan.

Other basic analyses include ILL transactions by large subject disciplines (based on LC classification) and net lender/net borrower status. More detailed analyses can determine, for example, which journal titles are requested more frequently than others, helping to establish journal acquisition priorities for libraries.

Methodology

Data documenting ILL transactions for Illinois were acquired from OCLC through their "PILLR" (Prism Inter Library Loan Reports) files. PILLR is a prototype program developed by OCLC to provide ILL data at the record level to libraries which allows them to manipulate the files as needed. Data available through PILLR provide a needed, necessary link between ILL and collection development in local libraries by providing libraries with information concerning ILL use by title and subject. The data is consistently collected and recorded greatly enhancing the potential for more accurate studies across libraries as needed by many consortia. PILLR’s pilot project status eventually ceased, and the program has since been folded into a more enhanced OCLC data reporting system, OCLC ILL Management Statistics.

OCLC ILL files for the 26 libraries in Illinois were collected and stored on a server in Dublin, Ohio. Due to a change in database management systems at OCLC, a total of 11 months, rather than 12 months, of data were made available to this project. Data from July 1996 through May 1997 were electronically transferred to the University of Illinois’ Library Research Center in Urbana, Illinois in late summer 1997. All ILL material types were included in the file transfer. For the purposes of this study, focus was placed on journal article requests for analysis. Monograph ILL data from OCLC for Illinois is considered incomplete due to the widespread use of the statewide online catalog in Illinois for lending and borrowing books. Therefore, monograph borrowing data is reported only in a very general way.

A complete list of the 26 libraries included in this study is found in Appendix A. The study group consists of 24 academic libraries, the Chicago Public Library, and the Illinois State Library.

The University of Illinois at Urbana-Champaign Library Research Center (LRC) was commissioned to collect and organize the ILL data. Ed Lakner of the LRC served as project supervisor. Data were loaded to the library file server and SPSS (Statistical Package for the Social Sciences) was employed to query the data. Analyses were conducted for all 26 libraries together, for libraries other than the 26, but still within the state of Illinois, and for libraries outside the state of Illinois.

Funding for the analysis was requested from the CCMCC. Support totaling $1,250 was awarded in December 1997. A graduate assistant was hired in spring 1998 to prepare Microsoft Access reports and spreadsheets. All funds were expended by August 31, 1998.

To better assess the data, a survey was sent to each of the 26 libraries’ Interlibrary Loan director. A copy of the survey questionnaire is found in Appendix B. The survey provided key information describing how libraries in Illinois use OCLC ILL systems. This information was used to clarify the data generated by OCLC and establish "norms" for the project.

Hypotheses

A number of hypotheses were established to provide queries to the database and to begin to define the nature of interlibrary article-photocopy use among the 26 largest libraries in Illinois. Seven broad hypotheses were developed to encompass different aspects of interlibrary lending.

1. The largest number of photocopy requests would be filled within the state of Illinois. The authors predicted a split of 60% filled within Illinois and 40% filled outside of Illinois.
2. The 26 libraries will be net lenders during the 11 months of the study.
3. Within Illinois, the 26 libraries will meet the most of the needs of the group of 26. The authors predicted that over 50% of all photocopy requests filled in Illinois would be met internally by the 26 libraries.
4. Photocopy requests filled within Illinois will come from the highest-requested titles. Photocopy requests filled from outside Illinois will more likely be for a single request for a single (unique) title. This hypothesis predicts that the "core" titles requested will be found within Illinois, and more peripheral titles will be borrowed from outside the state.
5. A core group of serials (not found in Illinois) will be identified that will be more cost effective to own and share within Illinois and which are now being accessed from outside the state. These titles will be used more than 20 times each in the eleven months.
6. Collection subject strengths will be identified by comparing the number of loans supplied and the number of article photocopies borrowed, based on Library of Congress Subject Classifications.
7. Subject analysis will show that the sciences (Q, R, S, T and W) have the highest number of article-photocopy transactions, both in borrowing and lending, as compared to other groups such as the humanities and the social sciences.

Data Summary

1. Total photocopy requests borrowed by the 26 libraries and filled either by the 26, within Illinois, or outside Illinois numbered 89,316. Fifty-eight percent of all requests by the 26 libraries were filled within Illinois and forty-two percent were filled outside the state, approximately a 60/40 split.

Figure 1.

Figure 2.

Summary: These data support hypothesis number one and show that Illinois’ libraries are meeting more than half of all the photocopy requests placed by the 26 largest libraries in the state. While the number of borrowed photocopies neared 90,000 in 11 months, it is critical to acknowledge that, based on ARL circulation data, interlibrary loan transactions may only represent about 1-2% of actual use taking place within individual library collections, meaning the onsite collections of the 26 libraries in the study could have local use approaching 9 million transactions in less than one year.

· The following give an indication of the 26 libraries’ lending activity.

Figure 3.

Summary: As expected, In-State loans (monographs) were outnumbered by photocopies supplied. This is due to the heavy reliance on the statewide online catalog for monograph lending and borrowing. These loans would not be expected to appear in OCLC borrowing and lending data. The out-of-state loans are accurate as those are accomplished on OCLC. Monograph data were removed from other analyses in order to focus on journal-article use within the state.

• Photocopies borrowed in-state totaled 52,179 and photocopies supplied in-state totaled 53,884.

Figure 4.

Summary: These data support hypothesis number two, which states that Illinois libraries would be net lenders during the 11 month study. The other in-state libraries were a net lender within Illinois showing the importance of those collections.

· Hypothesis number three states that within Illinois, the 26 libraries will meet most of the needs of the group of 26. The authors predicted that over 50% of all photocopy requests filled in Illinois would be met internally by the 26 libraries. Of the requests filled within Illinois, the 26 libraries filled 29,805 requests (57%), and the other in-state libraries filled 22,374 (43%) of requests generated by the 26 libraries.

Figure 5.

Summary: These data support hypothesis number three and confirm the interdependence the 26 largest libraries in Illinois have established in their journal collections. Despite this interdependence, other Illinois libraries are also providing tremendous support to "the 26" by supplying 43% of articles supplied. The importance of Multi-type Library consortiums is illustrated here as those collections can meet unanticipated research needs.

• Hypothesis number four addresses borrowed-title frequency. This hypothesis states that photocopies borrowed within Illinois will come from the most frequently requested titles, and that photocopy requests borrowed from outside Illinois will be for a single request for a single (unique) title. This hypothesis predicts that the "core" titles borrowed would be found within Illinois, while a single request from a single title would be more likely to be borrowed from outside the state.

Journal Titles Requested	Out-of-State	Within Illinois
% of all titles requested once	62.3%	43.7%
% of all titles requested 2-19 times	36.9%	53.0%
% of all titles requested over 20 times	.71%	3.2%

Figure 6.

Figure 7.

Summary: Data from the study support hypothesis number four. While the total number of ILL photocopy transactions measures overall activity, it is critical to determine the number of requests each title received. Less than one percent of requests that were filled out-of-state were for a high-use title (determined to be a title requested more than 20 times in 11 months). Conversely, over 60 percent of requests out-of-state were for single titles, compared to 44% within Illinois. These data show that high-use titles are more likely to be found within Illinois.

Illinois libraries are subscribing to large numbers of journals to meet researchers needs. Interlibrary Loan is supplementing that access, not substituting for it.

• Hypothesis number five looks again at borrowed-title frequency, but more specifically at the number of titles making up the most frequently borrowed group, those borrowed over twenty times in eleven months. The hypothesis states that a core group of serials (not found in Illinois) will be identified that would be more cost effective to own and share within Illinois and which are now being accessed outside the state.

Journal Titles Requested	Out-Of-State	Within Illinois
Number of titles requested once	9,882	5,414
Number of titles requested 2-19 times	5,865	6,517
Number of titles requested over 20 times	114	397

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Figure 8.

Summary: Hypothesis number five is supported by data showing the number of out-of-state titles requested over 20 times in 11 months. It has been estimated that it can cost two to three times more to access a title outside Illinois, making these 114 high-use titles easy to review for possible recommendation for purchase and sharing within the state. A review is required because while some of the titles may be high priced journals that few libraries can afford, other title requests are a reflection of the changing nature of research. They may be affordable but only needed for one short time by one researcher and a purchase may not be warranted.

· Continuing with borrowed-title frequency, a comparison was conducted to analyze the relationship between the number of articles borrowed and the number of journal titles needed to fill those requests. Expanding on hypothesis number four, which predicted that the most highly-requested titles would be located within Illinois, these data shows the number of transactions (borrows) per title, both in-state and out-of-state.

	# of Unique Title	# Transactions	Average Request Per Title
In State Libraries	12,382	51,889	4.19
Out of State Libraries	15,861	36,543	2.30

Figure 9.

Summary: The average request-per-title data show libraries in Illinois with 4.19 requests per title and out-of-state requests at nearly half that number, 2.30 requests per title. As predicted, higher requests per title were found within the state, meaning a more cost-effective use of those materials. In addition, the lower number of uses per title outside the state also result in a cost-effective use of materials. When few requests are made for a title, it is usually more economical to borrow that title than to own it. The highest average number of requests per title does not exceed the Copyright Guidelines CONTU rule of five (requests per title from the last current five years). While there are certainly some individual titles generating many more requests than that, it is reassuring to see that overall, that the average is below that.

· Hypothesis number six addresses photocopy transaction subject analysis. This hypothesis states that collection subject strengths will be identified by comparing the number of article photocopies supplied and the number of article photocopies borrowed based on Library of Congress Subject Classifications.

Figure 10.

Figure 11.

Summary: The data show the high borrowing and lending activity found among science disciplines (call numbers Q,R,S,T and W). Other high activity areas are H (Social Sciences ), B (Philosophy, Psychology, and Religion) and P (literature). But by far, and as would be expected, the sciences experience high traffic in both borrowing and lending, demonstrating that no matter how strong local science collections might be, it is still critical to establish borrowing agreements among peer institutions for additional access to science journals. The data illustrates the excellent breadth of the Illinois collections in that in most every case of LC range, more requests were supplied in-state.

• Hypothesis number seven states that subject analysis will show that the sciences (Q, R, S, T and W) have the highest number of article-photocopy transactions, both in borrowing and lending, as compared to other groups such as the humanities and the social sciences.

Figure 12.

Figure 13.

Summary: The data again show, by grouped subject areas, that the sciences experience higher levels of ILL activity (by nearly two to one) than either the social sciences or humanities. While this would be expected due to known differences in how each discipline uses information, the data do confirm that despite strong state-wide collections in science journal holdings, it is not possible to "own it all," and that an area to focus on in local collection improvement would be in the science fields.

Conclusions

The data reaffirms the critical role resource sharing plays in providing research material within the State of Illinois. Several important points have been made in this data analysis:

· a large number of articles are made available to researchers from state collections

· a majority of the high use titles are held in the state

· the importance of a statewide collection comprised of several library types,

· Illinois libraries are net lenders to the world

· the depth of the state collections as revealed by the number of unique titles available

· breadth as seen in the LC distribution.

· importance of these tools in determining purchase priorities

· Resource sharing is alive and well in Illinois

Recommendations

A number of recommendations can be made from the summary data.

1. Distribute local ILL use data to libraries. Offer seminar to explain/discuss the data.

2. Distribute a copy of this report to all participating libraries.
3. Ask IBHE to fund, with recurring money to cover inflation, the purchase of high-use journals previously borrowed outside Illinois. A full list of these titles is found in Appendix C.

4. Initiate and fund the creation of a statewide journal-holdings web site (or something such to facilitate ILL within the state?).

5. The State should pay for each of the 26 libraries’ OCLC ILL records, about 1,000 dollars per institution.

Appendices

1. List of 26 libraries in Illinois included in this study.
2. Survey sent to 26 libraries participating in the study.
3. List of journals recommended to own within the state of Illinois.

The 26 Illinois Libraries
OCLC lending/borrowing data available from 7/96 to 5/97

Augustana College
Bradley University
Chicago Public Library
DePaul University
Eastern Illinois University
Elmhurst College
Governors State University
Illinois Institute of Technology
Illinois State Library
Illinois State University
Illinois Wesleyan University
Loyola University of Chicago
Millikin University
Northeastern Illinois University
Northern Illinois University
Northwestern University
Roosevelt University
Rosary College
Southern Illinois University
Southern Illinois University at Edwardsville
University of Chicago
University of Illinois, Chicago
University of Illinois, Springfield
University of Illinois, Urbana-Champaign
Western Illinois University
Wheaton College

1.

What percentage of your filled photocopy lending is via OCLC?                What percentage of your filled photocopy borrowing is via OCLC?

Please give % breakdowns for other ILL mechanisms:
2.

LENDING: (example, 5% of the total copies supplies is through DOCLINE orders)                 DOCLINE:      Fax/Ariel/mail requests (note: this refers to how requests are made, not delivered!):      Other (i.e. RLIN; please specify):

3.

BORROWING: (example, 14% of copies received came via DOCLINE orders)      DOCLINE:      Fax/Ariel/mail requests: (note: this refers to how requests are made, not delivered!)      Other (i.e. RLIN; please specify):

For 1996-1997, please provide data on total ILL for photocopies:
4.

Total number of requests received from       your patrons to obtain a photocopy of something held at another library:__________________.      Total number of photocopies obtained for your patrons:________________.

5.

Total number of requests received from libraries       for you to photocopy something in your Collection and supply it: ______________________.      Total number of photocopies that were supplied:______________.

 
Please rank your lender preferences: (1= first choice of supplier)
     In State (ILSCO ILLINET) _________          CIC (if applicable)________
     LVIS group           _________          Other          __________
     
Please feel free to contact Lynn Wiley at (217) 244-1846 with your questions. Your prompt reply is appreciated. A postage-paid return envelope is enclosed. Thank You!