Economics and Usage of Digital Libraries: Byting the Bullet

8.7 Factors That Affect Demand

Clearly, demand for scientific journals is affected by price, but other factors affect demand as well. Scientists are willing to pay more for better journal attributes such as special electronic journal features, quality, speed of publishing, comprehensiveness and relevance of articles, and reputation of authors. In fact, studies in the 1970s suggest that such attributes were more important at that time than price. Our studies have shown that availability and relative cost of alternative sources of information determine to a large degree whether or not scientists and libraries will purchase journals. For scientists there are three types of alternative information sources. One alternative, discussed in Odlyzko (this volume), involves information from other research that has led to the research reported in an article or from near equivalent research done by others. A second alternative source exists because research results are often reported via a number of different channels, such as discussions, presentations, conference proceedings, technical reports, patents, and books, in addition to journal articles. A third alternative source involves the many distribution means and media in which journal articles are found. Alternative distribution means from which scientists can choose include personal subscriptions, library subscriptions, and separate copies of articles such as preprints, reprints, interlibrary loans and document delivery, and copies provided by colleagues, authors, and others. These distribution means can be in paper, electronic, or microform. The point is that numerous combinations of distribution means and media are used by scientists based on their assessment of availability and relative access costs.

Sources of articles that are read have changed dramatically over the years as shown by the proportion of readings from three sources in Table 8.5:

Clearly, scientists are reading less from their personal subscriptions, which undoubtedly is due to their subscribing to fewer journals (5.8 per scientist in 1977 to 2.4 in 2000-2003). Library-provided articles have been the alternative source of choice. The proportion of readings from other sources (e.g., shared department collections, colleagues, and authors) has remained consistent over the years. Few of these readings are currently from author web sites or preprint archives.

Our cost studies show that there is a break-even point in the amount of reading over which it is less costly to subscribe to a journal and below which going to the library or author source is less expensive. The break-even point, of course, is higher with higher prices. By knowing the distribution of sources among journals, we have determined the sensitivity of demand to personal subscription prices. We have also shown that scientists' time is an important component in the cost equations, and that scientists generally behave in an economically rational manner in deciding whether or not to purchase a journal. For example, distance to the library also affects the break-even point and the purchase of journals. As corroborating evidence, we have observed that

• Scientists close to libraries purchase fewer personal subscriptions than those further away (e.g., 1.8 subscriptions per person for those less than ten minutes away versus 2.6 for those further away).

• Scientists close to libraries and shared department print collections read more from these sources than from personal subscriptions (e.g., 91 percent of readings by those less than 5 minutes away; 65 percent for those 5 to 10 minutes away; 43 percent for those more than 10 minutes away).

• Even with availability of electronic personal subscriptions, most scientists prefer to subscribe to print versions. This may be because, as we have observed, it takes them less time to browse current print journals than electronic versions. However, when library journals are available online, scientists prefer to browse these journals online because it saves nearly 15 minutes per reading by not having to go to the library to browse or obtain older articles.

It is clear that the relative cost of alternative sources is important and that scientists' time is an essential component of cost that must be kept in mind. Now that scientists can obtain some copies of articles online, the choice is complicated somewhat. However, as will be discussed later, amount of reading from a journal and scientists' time both remain dominant factors in the decision.

Libraries are faced with similar choices between purchasing (in paper or electronic media) or relying on obtaining separate copies of articles. The amount of reading of specific journals, their price, and the cost of obtaining separate copies are all important factors which should play a role in decision-making.[13] Over time, scientists pretty well know how much they will read a journal, but it is more difficult for libraries to establish the extent to which individual journals are used, particularly with electronic journals. With print versions, common practice is to ask library users to leave journal issues and bound volumes on the table to be counted when re-shelved (or to use circulation bar codes). A weakness in this method of observation is that use of an issue (or bound volume) may involve reading of several articles and all readings should be counted when deciding between purchase or obtaining separate copies of articles. However, reasonable adjustments can be made to the use data.