I then took a low-end conservative figure for OAc at 50% and applied it to
the conservative figure of 85% not yet self-archived, to yield 50% x 85% x
£3.5.bn = £1.5bn worth of loss of return (in terms of citations) on the
RCUK's £3.5.bn annual investment.
As noted, it is not the number of articles published annually (about
130,000) that represents the return on the UK's research investment; it is
how much those articles are used, applied, and built-upon. Research
published but not used, applied and built-upon is research that may as
well not have been done or funded at all. The citation counts are measures
of the degree to which research is used, applied and built-upon --
"research impact."
The UK is losing 1.5bn worth of potential research impact annually (on our
conservative, low-end estimate) for the 85% of it that it is not yet
self-archiving (another conservative estimate). The RCUK open-access
self-archiving mandate -- *if* it is not hobbled into an open-ended
embargoed-access policy, as the NIH policy proposal was -- will remedy all
of this needless loss of research impact and return on the UK public
investment in research.
Please note that I did not say the UK was getting *no* return on its
research investment: Even non-OA articles get used and cited -- but only
by those users whose institutions can afford the toll access to the
journal version. The empirical 50-250% citation-gap corresponds to the
loss of the potential research impact from those users who are currently
denied access. Self-archiving the author's version is done to maximise
usage, impact, and hence the return on the public investment, by making
the research accessible to those access-denied would-be users too.