spobooks5621225.0001.001 in
    Online Versus Paper: Usage Data

    Our data (based on comparison between the online book usage figures and data collected through circulation statistics and slips placed in corresponding reference titles in the library) suggest that online books were used more than their print counterparts. If we count circulation alone we find that there were about three times as many accesses per book online as for the paper version. After consultation with librarians we believe that a reasonable correction for in-house use is to increase circulation by 50%. This would reduce the ratio to twice as many online uses per book.

    Figure 16.5: Histogram of time since first useFigure 16.5: Histogram of time since first useNOTE: Height of the bar is the number of sessions logged by users starting the indicated number of days before data collection.

    We conjecture that higher usage for online books is due to lower convenience costs than for other access options. Having purchased a paper copy for the library does not ensure that the book is available. The book might be in circulation, or missing from the shelf. If the library is closed the paper copy of book is not available to a user. A common access option is an online public access catalogue (OPAC). However, an online public access catalog does not support even the roughest form of browsing into the book until the book itself is put online. An OPAC provides so little information about a book that a scholar might not be aware that it contains material relevant to his work. If so, the mere ownership of that book by his library does not make it truly available to him. Catalog records enhanced with tables of contents and book indexes are a relatively new offering and a major asset to the scholar in locating books relevant to his or her research, but do not eliminate the higher convenience costs of accessing the physical book at the library.

    Hence, the online access to a full book represents a quantum leap in the availability of the contents of that book, and, we believe, lowers the barriers to access for many modalities. Perhaps the only modality for which it is not clear that online access is preferable is "plain old reading at length."

    We were also interested in studying patterns of access when readers use online books. We have approached this in two different ways. One is essentially qualitative, in which we asked people in surveys and in interviews how they used online books. In doing that we were able to identify at least the following kinds of activity: browsing, grazing (that is, reading portions of text scattered through the book, punctuated by visits to the index or table of contents) citation checking, the finding of individual facts or quotations, reading on reserve for a course, determining the need for a paper copy, printing (that is, turning the online book into paper), and directly reading online.

    We have also, because we can track individual users, been able to break some new ground in quantitative analysis of how people use books online. Generally, each chapter is a separate file, and hence a separate entry in the web sever log. Thus, by analyzing the sequence of clicks on chapters, we are able to distinguish a number of different ways in which individuals use online books. The first style we characterize as linear use: an individual reads chapters of a book in exactly the same order in which they appear in the printed volume. The second pattern of use is quasi-linear, in which the sections of the book are visited in some personalized order but each section is read once and only once. We also observe a pattern we call hyper-linear, in which sections are visited in an arbitrary order and some sections are visited more than once. Hyper-linear usage occurs about 12% of the time. See Figure 16.6.

    Figure 16.6: Patterns of motion in online booksFigure 16.6: Patterns of motion in online books
    Figure 16.7: Use of index in online booksFigure 16.7: Use of index in online books

    There are several ways that a use pattern may involve use of the index (or, more generally, search tools); see Figure 16.7. The first format is to use a search tool once, at the outset, and then to view portions of the book in some linear or quasi-linear order. Another possibility involves using the index, going to a section, and then going back to the index and out to another section and continuing in this pattern. Whether this is a natural behavior evolving in the presence of online books or an artifact introduced by the fact that returning to some index or search tool may be the easiest way to get to the next section is something we don't know at this point. In thinking about these patterns of use, we may compare them to what a person might do with the book in hand, at the library shelf, or with access to the catalog, in some online format.