Trends in Ebook Usage from 2008 to 2012

Overall aggregate usage of ebooks from 2008 to 2012 has increased from 89,625 uses to 1,188,158 uses or 1226% (Fig. 2). Greatest annual increase in aggregate usage was 196.4% from 2009 to 2010. The vendors being compared year to year are not exactly the same for each year. The usage units reported by each vendor are mostly section requests but the aggregate usage also includes other units such as title requests and accesses.

Fig. 2. Usage for all vendors for the period 2008 to 2012.

Titles can show a big drop in use from one year to the next even though more titles became available. The Royal Society of Chemistry ebooks decreased in usage by 40% from 2011 to 2012. IEEE had a 9% decrease in usage from 2011 to 2012.

Single titles can account for a high percentage of annual usage such as the IEEE title, Renewable and Efficient Electric Power Systems, which received 10% of all IEEE chapter requests in 2012.

Usage trends within a calendar year typically show a semester pattern with a bimodal distribution of higher use during spring and fall months. Occasionally there is high usage is in the summer such as Gale ebooks in 2011 which had the most use in June and fourth highest use in July.

Some vendors show unusually high levels of usage for one or a few months which could be legitimate use due to course assignments or it may be due to systematic downloading.

A very rough estimate of cost per use of all vendors for which we have cost data was approximately $0.90 per use in 2012. Cost per use was not determined every year.

Usage Trends for Major Vendors

Vendors receiving high use from 2008 to 2012 are Springer, Ebrary, EBSCO/NetLibrary, Wiley and Safari. Ebrary, EBSCO/NetLibrary and Safari are aggregators. Ebrary has shown the highest use for any vendor, assuming that section requests as units of usage are similar across vendors. Ebrary usage increased 1469% from 2009 to 2012 (Table 1).

Table 1. Per cent change in usage for selected vendors over four or five year intervals.

In 2012 Ebrary had the highest use with 813,168 section requests while Springer was second highest with 109,964 section requests; however, the difference may not be as great as it appears since Ebrary treats pages as a section and Springer treats chapters as a section.

In 2012 Ebrary section requests per title (for those titles which received use, not the number of available titles) decreased 30%. This is the first time this measurement decreased since 2009 and it may indicate that we are reaching a saturation point in usage since there is now an abundance of choices for ebook titles.

Table 2. Ebrary section requests per title for 2009 to 2012.

Springer usage has increased every year from 2009 to 2012. Springer covers a narrower range of subjects than Ebrary.  Springer usage increased 226% from 2009 to 2012 (Table 1).

Wiley usage has increased every year since 2009. Usage increased 250% from 2009 to 2012 (Table 1). Reference works are among the most used Wiley titles, specifically eLS (Encyclopedia of Life Sciences), Ullmann’s Encyclopedia of Industrial Chemistry, and Kirk-Othmer Encyclopedia of Chemical Technology, which appear among the five most used  titles for 2009 through 2012.

EBL has shown low usage from 2008 to 2012 which reflects the low number of titles we have purchased. EBL title requests increased 25% from 2008 to 2012 (Table 1).

In July 2011 NetLibrary became EBSCO eBook Collection so the vendor is represented here as EBSCO/NetLibrary. There has been a leveling off of usage for this vendor in recent years in parallel to the decrease in purchasing of these titles.  In usage reports Netlibrary reported accesses and EBSCO reports title requests but they appear to be equal units. For the period 2008 to 2012 EBSCO/NetLibrary reached a peak in usage of 15,532 accesses in 2009. Usage from 2008 to 2012 increased only 3% (Table1).

EEBO (Early English Books Online) had a high of 15,025 full records accessed in 2009, much higher than the 10,418 full records accessed in 2012. EEBO usage decreased 31% from 2009 to 2012 (Table1).

Safari aggregates ebooks from a range of technology publishers. Safari section requests have increased every year from 2008 to 2012 except for 2010. Usage increased 267% from 2008 to 2012 (Table1).

ABC-CLIO  showed erratic usage for 2008 to 2012 as measured by title requests or section requests. Over this period title requests have decreased 6% (Table1). The greatest increase in section requests for ABC-CLIO was 840% from 2011 to 2012. This increase was due to an overall increase in usage and not just a few titles receiving very high usage. ABC-CLIO has a relatively small number of titles so that if a small number of titles receive increased use it can have a big effect on percentage change in yearly use.

Conclusions/Recommendations

In order to make more valid comparisons between vendors we need standardization of section requests. Even though section requests are reported by most COUNTER-compliant vendors a section request can be a page, a chapter, or another unit. It would also be very useful to receive usage reports from vendors which show just our owned or leased titles. Typically vendors show only the titles which received use or all of the titles which they sell. In the first case we do not see which titles received no use and in the second case many titles which we do not own show up as having zero use.

Vendors such as Springer and Ebrary, from which we purchase a large number of titles, tend to have high usage. Increases in usage from year to year are due in part to purchase of new titles.