Adelphi University Libraries started an ebook Demand Driven Acquisitions (DDA) program with ebrary in January, 2014. After one short term loan a second use triggered a purchase. This trigger was determined by an analysis of how ebooks were used in the subscription component of ebrary, Academic Complete. Titles were added to the pool according to our slip plan profile with YBP. Librarians could also manually add ebook titles to the DDA pool.
To see if our trigger point should be adjusted for our current DDA with ProQuest Ebook Central, I pulled statistics from the ebrary administrative portal for January, 2014 through January, 2017 that show the use of items after they have triggered a purchase. My analysis covers the subsequent use of items that were triggered for purchase; the value of the DDA program compared to if we had purchased the ebooks outright; the value of including publishers such as Wiley that do not allow short term loans in a DDA program.
With the use of other Adelphi ebook usage stats my assessment also covers the value of this DDA program for ebooks compared to the usage of ebooks in our subscription database and our firm ordered ebooks. In this context I also consider what benefits accrue to publishers in supporting DDA programs for ebooks as opposed to other acquisition and access models.
