Ying Zhang (Acquistions Librarian from University of Central Florida) did some analysis of her institutions use of ebooks acquired using one of three possible purchase methods. She measured ROI by calculating how many uses ebooks got for each $10 invested in each of the three methods.
Patron Driven Acquisition (PDA)
Titles acquired based on user demand
Titles selected and acquired individually
Large pre-defind static collections acquired as one time purchases
Although this ROI measure makes it look like 'Package' is the best for ROI Ying makes the point that each method has it's place:
- Package has the highest ROI but is stagnant and use will drop over time. The library and it's users can't weed out unwanted titles or add wanted ones.
- Firm is how you shape and customise your collection, but has the highest admin costs.
- PDA provides a low input mechansim by which the collection updates itself to the user's needs.
He found that titles were roughly evenly spread between Social Sciences, Arts & Humanities, and STEM.With Social Sciences having 15% more titles then STEM, which in turn had about 1.5% more titles than Arts & Humanities.
Reverse engineering from his bar chart I get a 'use ratio' for Social Science titles that is 32% higher than STEM titles (in spite of the higher number of titles) which in turn has a 'use ratio' of 15% higher than Arts & Humanities
This is sort of counter intuitive given A&H perceived reliance on monographs, but as Michael continues to look at the stats interesting things pop up:
- STEM titles average far more pages per session (scanning?)
- Arts & Humanities spend the most time per session and per book (immersive reading?)
- His graph by LC number of number of titles available compared to usage shows that L(Education) titles get he most usage followed by N J T H M R D E, Z gradually tailing off with the last 5 classifications being Q P K U and F