Trends in interlibrary lending: a longitudinal data analysis on article sharing in Italy

Interlibrary loan (ILL) article sharing data among member libraries within the Italian Network for Inter-Library Document Exchange (NILDE) for 2005-2009 and 2011-2015 have been collected. NILDE is the largest ILL network in Italy with almost a thousand libraries consisting mainly of university libraries, as well as libraries in hospitals and health research institutions, public research institutions, and not-for-profit organisations. ILL request data collected from the NILDE system are analyzed. The present study replicates the methodology and data analysis of the authors' previous work for 2005-2009, with the aim of monitoring the changes which have taken place in article sharing over the past eleven years within Italy. Results show an overall steady growth in the number of ILL article requests peaking in 2014, notwithstanding the widespread introduction of Big Deal subscriptions from the early 2000s and e-journal subscription growth across academic, research and hospital libraries, so that the increased availability of electronic resources did not seem to have led to a reduction in ILL requests. The longitudinal data analysis shows an annual rise in requests for newer articles, suggesting an increasing demand for recently published documents. An initial inversion of this trend, starting in 2015, was observed, although not homogeneous per library disciplinary field. Should this trend be confirmed for 2016, further analysis could focus on new habits in peer-to-peer resource sharing through social research networks such as Researchgate, Academia.edu or Open access availability of publications, i.e., users' unmediated document retrieval.