The impact factor of a journal is a measurement of the frequency that an average article in that journal has been cited by others over a set period of time. Journal Impact Factor is used as a quantitative tool in the evaluation of journals and the academics who publish within them.
There are 3 key resources which measure Journal Impact Factor and the quality of the research that is held within academic journals. As each service assesses a different set of journal titles, comparisons between results from the different sources are not reliable.
Citation data - academic researchers may wish to know how many times their work has been cited by others and which articles are the most highly cited ones in their discipline. These resources will also provide that information.
Journal Citation Reports give the impact factor of each journal that it indexes.
The impact factor is a measure of the frequency with which the average article in a journal has been cited in a particular year or period. The annual Journal Citation Reports impact factor is a ratio between citations and recent citable items published: a journal's impact factor is calculated by dividing the number of current year citations to the source items published in that journal during the previous two years.
SCOPUS allows you to search for an author or researcher, see their cited documents and view their h index.The h Index was developed by J.E. Hirsch (see: Hirsch, J. E., 2005. An index to quantify an individual's scientific research output. Proceedings of the National Academy of Sciences of the United States of America, 102, 46, pp. 16569-16572.)
Simply put, a h index indicates that a researcher has published h papers which have been cited in other research papers at least h times.
SCOPUS also provides alternative journal impact measures SNIP, IPP, and SJR. These are found within the SCOPUS database, or the Journal Metrics website.
Google Scholar Metrics cover articles published since 2007. You can set up a "My Citations" account to identify all citations to your research in GS.
"Google Scholar Metrics provide an easy way for authors to quickly gauge the visibility and influence of recent articles in scholarly publications. While most researchers are familiar with the well-established journals in their field, that is often not the case with newer publications or publications in related fields - there are simply too many of them to keep track of! Scholar Metrics summarize recent citations to many publications, to help authors as they consider where to publish their new research." (Google Scholar, 2012. Google Scholar metrics. [Online] Available at: http://scholar.google.co.uk/intl/en/scholar/metrics.html (Accessed: 3rd September 2012))
