Résumé
COVID-19 challenged information exchange globally, including interlibrary loan (ILL). This project explored DOCLINE ILL borrowing data from 15 academic, hospital, and association health sciences libraries before and during the pandemic to understand gaps in ILL coverage. We reviewed aggregate filled and unfilled borrowing data from March to August in 2019 and 2020. We compared these time periods to each other and to system-wide fill rates. We normalized journal titles, added journal price and language, calculated descriptive statistics and odds ratios, and conducted 2-proportion z-tests of differences. In our sample of 14,891 requests, the odds of requests being unfilled were 2.7 times higher in 2020 than in 2019. While the proportion of non-English language content requested did not change, a significantly higher proportion went unfilled in 2020. The rate of unfilled requests for older items also rose significantly between 2019 and 2020. Our findings support the conclusion that the COVID-19 pandemic significantly influenced ILL article request fulfillment in health sciences libraries. Libraries should consider collection development strategies to increase the accessibility of articles held only in print, and those with specialized print collections may want to prioritize digitization of older materials. Future research on the availability, utility, and expense of the materials more likely to remain unfilled should inform publisher backfile prioritization as well as consortial and individual library collection development practices. © 2023, Association of College and Research Libraries. All rights reserved.