"Global comparisons of scientific output are commonplace. As non-experts, policymakers and administrators must rely on indexes of impact and recognition — counts of published papers and citations, and the prestige of source journals — to assess the impact of public spending and to allocate research funds.......
"In a recent study we counted more than 15,000 scientific periodicals among the 'BRIC' countries (Brazil, Russia, India and China), of which just 495 — about 3 per cent — are listed in SCIE.
"Amazingly, this is not an anomaly: we found that SCIE lists only about 3 per cent of journals for most scientifically advanced countries.
"This means that decision makers anywhere in the world relying on SCIE (or its cousins, Scopus or perhaps Google Scholar) do not account for, access, or compare as much as 90 per cent of scientific output — works we call "unseen science"."
Caroline Wagner. SciDev.Net
19 July 2012