I made some errors in the last few posts, making the information somewhat scrambled -- my apologies. Here is what I hope is a clear picture of what we know about the relative costs of OA and TA publishing.

1. The NIH estimates that it pays $100 million/year in author-side charges, and supports the production of some 80,000 scholarly articles; that's an average of $1250/article.

Update: Peter Suber points out that some fraction of that 80,000 articles did not use NIH funds, either because they were published in no-fee journals or because the authors found other ways to pay. I can't think of any way to estimate the actual number of articles the $100 million paid for in order to adjust the estimated fee/article, but it's worth remembering that it's an underestimate.

2. Björk et al. found that less than 5% of all articles worldwide are available through no-embargo Gold OA. We don't know what proportion of the NIH's $100 million went to Gold OA fees, nor what the average such fee might be. In order to be conservative, let's assume that the average Gold OA fee is triple the average TA fee (it almost certainly isn't that high). Then (if that 5% is evenly distributed) the NIH paid for (0.95x80000=) 76,000 articles at $average and 4,000 articles at 3x$average, bringing the average author-side charge for a TA article to $1136.

3. Philip Davis' 2004 library costs spreadsheet estimates the average subscription charge per scholarly article at between $970 and $1750, depending on what proportion of the library serials budget is allocated to scholarly publications.

Davis' original study estimated this proportion at 50% (on what basis I don't know), but I think the real value is closer to 90%. My reasoning is based on my observation (see Table 2) that the average unit cost of a curated list of scholarly journals from UCOSC is about ten times the average unit cost of "all serials" from ACRL, ARL and NCES datasets. If that result is broadly representative it means that scholarly journals must contribute either a small fraction or the vast majority of the cost (see here for a brief explanation).

So that gives an estimated fee of between $2106 and $2886 per toll-access article. That money isn't all coming from the same place -- the NIH is paying author-side fees and libraries are paying subscriptions -- but it's all going to the same place, publisher coffers.

I've added a current (under)estimate of NIH costs for author-side fees, adjusted for a 2006 estimate of %OA by article, to a 2004 estimate of subscription fee/article, but I'm confident that the real cost (if I could get up-to-the-minute figures for all inputs) would be in the same ballpark.

Sure puts one-time, up-front Gold OA fees in a different perspective, doesn't it? Here's a reminder (stupid Impact Factors in brackets just because I know a lot of people still think they mean something even though they don't):

¹ Update: since D0r0th34 has already pointed out one dumb thing I did, neglecting other revenue streams available to TA but not OA publishers, I think that rather than continually update this post I'll just go ahead and embed the FriendFeed discussion right here: