From: Lloyd Davidson <[log in to unmask]> Date: Wed, 25 Jan 2012 21:08:12 -0600 While pay-for-use certainly pertains to books, an important area that has its own set of issues, the major discussion of academic pay-per-use systems involves the underwriting of journal article access, which is where most academic library funds are spent, at least in the sciences, although a great deal of funding also goes for subscriptions to expensive databases like Web of Science and Chemical Abstracts that provide bibliographic access to these journals. The two systems, monograph vs. journal purchases, certainly have many parallels but monographs make up a relatively small proportion of at least most science library acquisitions and ILL can provide adequate access to most of those mongraphic works that a library does not purchase, as long as there is some lead time before they are needed. I can't imagine a pay-per-use metric that would automatically lead to a purchase (i.e. subscription) of a journal title, at least not one of the more expensive ones ($20,000 or more a year) and libraries typically request copies of individual articles, not whole journal issues. While a book approval plan has some superficial similarity to journal subscriptions, the two systems are wildly different in their function. The idea of allowing open purchases of journal articles by faculty and students until a spending cap is reached would create a disastrous chaos among researchers, where anybody's need who ordered articles before the limit was meant would be served and everybody who requested an article after that, e.g. after April 1 in major research institutions, would either have to pay for such articles out of their personal or their grant's funds or do without. The bookkeeping costs alone of such a system could cost many thousands of dollars a year. BTW, due to increased "handling charges" resulting from the processing of article orders, I foresee the cost of individual articles increasing far faster than even the cost of journal subscriptions, which is already well ahead of the rate of inflation. Lloyd Davidson On Jan 25, 2012, at 6:16 PM, LIBLICENSE wrote: From: Sandy Thatcher <[log in to unmask]> Date: Wed, 25 Jan 2012 10:35:29 -0600 Is not PDA a form of "usage-based pricing" for books? PDA services provide access to all (or almost all) of a publishers' books, and a usage metric determines when a purchase occurs. A budget for PDA provides a "cap" on how much money is to be spent in this way every year. This contrasts with the "approval plan" model where all books fitting a certain category are purchased without regard to demonstrated actual need, much as a subscription provides access to all articles in a journal regardless of how many of them are actually ever used. Are there significant differences I'm missing? Sandy Thatcher