The fee-based Science Citation Index now has some competition from the new, free SJR-SCImago Journal & Country rank system. This new service utilizes data from Elsevier's subscription based Scopus database to provide a free source of scholarly journal rankings. Scholars now have an alternative to the previously unchallenged "impact factor" method of comparing the relative importance of journals. The SCImago Journal Rank (SJR) can be used as alternative means of determining the measure of a journal's citation impact. SCImago works by using an algorithm similar to Google's PageRank. Unlike the Impact Factor, SCImago weighs citations from journals according to how highly cited each journal is. Whereas in the standard impact factor approach, every citation has an equal weight. The beauty of the weighted approach by SCImago is that more highly weighted journals such as Nature or New England Journal of Medicine will rank higher. Another difference between the Impact Factor and the SJR is that the SJR calculation looks at citations from a three year period. Because of this, the SJR is a more consistent indicator of trends than impact factors which can vary significantly from year to year.
One major disadvantage of SJR is that the current coverage period for country and journal indicators is only 1996-2007.
You can search SCImago by journal title, keyword, subject and country. You can even create graphs that compare journal titles and export data to Excel.
Here's what the information looks like for the Journal of Advanced Nursing.
Here's a comparison of 4 important nursing research journals:
1999 2000 2001 2002 2003 2004 2005 2006
Nursing Resarch 0.083 0.070 0.097 0.086 0.109 0.111 0.139 0.138
Journal of Advanced Nursing 0.061 0.069 0.069 0.075 0.081 0.083 0.085 0.104
Clinical Nursing Research 0.052 0.058 0.059 0.062 0.063 0.074 0.078 0.091
Western Journal of Nursing 0.050 0.051 0.054 0.055 0.057 0.065 0.079 0.089