Following on from part 2, I thought I'd ask a couple more questions about price-per-use, based on the online usage stats in the UCOSC dataset. I started on this because I noticed that in Fig 2 of part 2, I'd missed a point: there is an even-further-out outlier above the Elsevier set I pointed out:

It's another Elsevier journal, Nuclear Physics B. In 2003, only 1001 online uses were reported to UC by the publisher, but the 2004 list price was $15,360. The companion journal Nuc Phys A is not much better, $10,121 for 1198 uses. Compare that with Nature, 286125 uses at just $1,280!

It gets worse, too, because I'm led to believe that anything that appears in a physics journal these days is available ahead of time from the arXiv. I tried to confirm that for Nuc Phys B, but either I'm missing something or the arXiv search function is totally for shit, so I couldn't do it systematically. I did go through the latest table of contents (Vol 813 issue 3) on the Science Direct page, and was easily able to find every paper in the arXiv -- mostly just by searching on author names, though in a couple of cases I had to put titles into Google Scholar. Still, they were all there, which leads me to wonder why any library would buy Nuc Phys B (or Nuc Phys A, assuming it's also covered by the arXiv). Prices haven't improved in the intervening 5 years, either:

[I had a table here but Movable Type keeps munging it. Piece of shit. Here's a jpg until I sort it.]

That got me wondering how the rest of the journals are distributed by price/use and publisher:

The inset shows a zoomed view but even that wasn't particularly informative, so I zoomed in a bit further:

The curve fits are for the whole of each dataset, even though it's a zoomed view; the Nature set excludes British Journal of Pharmacology, the only NPG title that recorded 0 uses, and Nature itself. Colour coding by publisher is the same for each figure in this post. As in part 2, the correlation between price and use is weak at best and doesn't change much from publisher to publisher. Also, each publisher subset shows a stronger correlation than the entire pooled set -- score another one for Bob O'Hara's suggestion that finer-grained analyses of this kind of data are likely to produce more robust results. Since cutoffs improved the apparent correlation for the pooled set, I tried that with the publisher subsets:

As in part 2, with uses restricted to 5000 or fewer there was improvement in price/use correlation in most cases, but nothing dramatic; I'm not sure why the Blackwell fit got worse. The Nature subset is close to being able to claim at least a modest fit to a straight line there, so not only does NPG boast some of the lowest prices and highest use rates, they are the closest of all the publishers to pricing their wares according to (at least one measure of) likely utility. Special note to Maxine Clarke, remember this post next time I tee off on Nature! :-)

Next, I broke the data out into intervals (for clarity the labels say 0-1, 1-2 etc, but the actual intervals used were 0-0.99, 1-1.99 etc):

Now it seems that we're looking at some kind of long-tailed distribution, which is hardly surprising. The majority of the titles fall into the first few price/use intervals, say less than about $6/use. Since most pay-per-view article charges are between $25 and $40, I more-or-less arbitrarily picked $30/use as a cutoff and asked how many titles from each publisher fall above that cutoff, and what proportion of the total expenditure (viz, list price sum) does that represent? The inset shows that 161 titles, most of them from Kluwer and Springer (whose figures I combined because Springer bought most of Kluwer's titles sometime after 2003), account for about 5% of the total in list price terms. That was a bit more useful, so I expanded it to ask the same question for each interval:

What becomes apparent now, I think, is that the UC librarians are doing a good job! Only 6% of the total number of journals (5% of the total list price cost) fall into the "more than $30/use" category, of which it could reasonably be said that the library might as well drop the subscription and just cover the pay-per-view costs of their patrons. Only a further 15% or so work out to more than $6/use, and around 80% of the collection (figured as titles or cost) comes in under $6/use, with around 30% less than $1/use.

So, are these reasonable prices -- $1 per use, $6 per use? I'm not sure I can, but I'll try to say something about that question, using the UCOSC dataset, in Part 4.