Details on the price and lifespan data

Print prices

The print book prices shown on the Library eBook cost crisis page come from a consortium of small rural libraries that contracts with Ingram. To determine whether the prices are typical, we also checked the invoices for

• a county library system using Ingram

• a city library system using Baker & Taylor

It is common for public libraries to contract with book distributors and to receive a volume discount of 40-43% of the publisher list price.

Print lifespan

Our lifespan calculation of 6 years comes from an analysis of the collection at Whatcom County Library System. The titles in the data set:

• include all adult fiction and nonfiction collections, including paperbacks

• exclude special collections such as Local History, which have unusual retention procedures

For 48,000+ withdrawn items, Whatcom County Library System determined for each item the date it was first available to circulate and the withdrawal date, and calculated the difference as the lifespan. We then calculated the median lifespan for all items, 6.5 years, which we have rounded down to 6.

This calculation includes items that are withdrawn due to loss or damage, but these are a relatively small proportion of the whole: ~2%.  Most items are withdrawn due to waning patron interest and/or a need to make room for new books.  Also, the library’s mission to collect and offer a broad range of subjects, genres and authors means that the vast majority of our books circulate modestly, not continuously. These take years to reach a circulation count that prompts libraries to withdraw because a book is worn out.

Very popular books do circulate continuously while they are "buzzing” and some of these will be damaged or lost. However, libraries usually buy multiple copies of popular books to meet demand, and for each damaged or lost copy, there are several that survive the first year and thereafter will circulate moderately for a decade and more.

Book lifespan is likely to vary by library depending on a number of factors, including:

• circulation

• shelf space

• collection budget

To test whether the 6 year estimate is typical, we requested lifespan analysis from several libraries that vary by size. Thanks to the information below, we are comfortable that our use of a 6 year print lifespan is a reasonable (even generous) value to use as a baseline in our apples-to-apples cost comparison.

eBook Prices

eBook prices were taken from OverDrive, the eBook platform that at least 90% of US public libraries use. For all major publishers except HarperCollins, library eBook licenses expire after 2 years.  The totals shown are the cost to the library of a 2 year license a total of three times sequentially, providing patrons access for 6 years.

The Women: Macmillan charges $60.00 for a 2 year license in the first year of release and thereafter reduces the cost to $55.00, so providing one copy patrons for 6 years costs $170.00.

Tom Lake: HarperCollins uses a license that expires after 26 loans rather than 2 years. For eBooks that circulate continuously, as Tom Lake has done, a 26-loan license will last a library an estimated 15 months. Providing the book for 6 years therefore will require the library to acquire 5 licenses sequentially.  At $42.09 for a single license, access for 6 years will cost $210.45.