The Research Information Network has released The UK's Share of World Research Output: An Investigation of Different Data Sources and Trends.
Here's an excerpt from the announcement:
Bibliometrics have come to play an increasing role in assessing the performance of researchers in the UK, as indeed in other parts of the world. But the complexities of both the data sources and the methods of analysis used are little understood by many of those who wish to make use of the results. Even the relatively simple matter of measuring the UK’s share of the global production of scientific publications is much more complex than appears at first sight, with traps for the unwary and huge differences in the published figures.
The RIN's The UK's share of world research output report explains how these difference arise, and reflects on the implications for the measurement of UK scientific performance. It highlights that producers and publishers of bibliometric data must make much more transparent the choices they have made as to data sources and methodology, and the implications of those choices. Policy-makers and others interested in the health of the UK research base must also take greater care to interrogate the figures that they use and to present them accurately. Otherwise the risk is that policy and related decisions will be made on the basis of false assessments.