JCR vs. SCImago
Nature Publishing Group just announced that its flagship journal Nature has the highest journal Impact Factor (36.101) and has most citations (over 500,000), based on data from the recently published 2010 JCR. Journal Citation Reports (JCR) is published annually by Thomson Reuters and uses data from the 2 previous years. We no longer subscribe to the JCR, so I decided to look at SCImago Journal & Country Rank and see their journal rankings for 2010. SCImago Journal & Country Rank is a product of SCImago, a research group from the Consejo Superior de Investigaciones Científicas (CSIC), University of Granada, Extremadura, Carlos III (Madrid) and Alcalá de Henares. SCImago Journal & Country Rank is based on data from the Scopus database, for the 3 previous years. It is freely available. SCImago uses 2 measures to rank journal impact: SCImago Journal Rank (SJR) and H-Index.
The top 5 journals ranked by SJR are: 1. Annual Review of Immunology, 2. Nature Genetics, 3. Cell, 4. Ca-A Cancer Journal for Clinicians, and 5. Immunity. Nature is ranked 8th.
The top 5 journals ranked by H-Index are: 1. Nature, 2. Science, 3. New England Journal of Medicine, 4. Cell, and 5. PNAS.
The journals can be sorted and ranked by other fields. For example, the top 5 journals ranked by total citations are: 1. PNAS, 2. Nature, 3. Science, 4. Journal of the American Chemical Society, and 5. Journal of Biological Chemistry.