Impact Factor
Publishing in high-impact journals can be important in establishing your status in your field.
How do I access Impact Factors?
Impact factor tables are available through the Journal Citation Reports database via the Web of Knowledge.
A journal's impact factor is based on how often articles published in that journal during the previous two years (e.g. 2008 and 2009) were cited by articles published in the most recent year for which JCR data is available i.e. 2010. Therefore a journal with a high impact factor indicates that articles in that journal have been cited frequently by other articles. This can be an indication of how prestigious a journal is in its field.
Interpreting Impact Factor Data
When interpreting impact factors there are a number of important influences to consider:
- Field or discipline variation: not all journals have impact factors, and the importance of impact factors will vary between disciplines.
- Some disciplines/subject categories may naturally publish fewer articles than in others (because of a potentially smaller research pool), therefore making for a lower impact factor.
- New journals: will have a low impact factor simply because they have not been available long enough to establish themselves.
- Not all research work is cited in citation indices: The impact factor produced by the JCR database is a reflection on the data indexed by the ISI Web of Science.
- Impact factor influences: scores can be significantly influenced by a few highly cited articles and/or too many un-cited or low-cited articles.
- Review articles: authors and journals that frequently publish review articles tend to have their citation counts and impact exaggerated because these types of articles are usually highly cited.
- Non-cited articles: citation counting and impact factors do not take into account articles that were used but did not get cited.
- Longevity: the two-year “citation window” in the impact-factor formula fails to capture the “long-term value” or the real impact of many journals. The five-year impact factor may therefore be a better indicator for some disciplines, e.g. the Humanities.
- Negative citations: The index ignores why an item was cited in the first place so negative citations to incorrect work are counted.
Scopus Journal Analyzer
Scopus Journal Analyzer is another tool that allows you to compare journals using its own journal ranking metrics. The SCImago Journal Rank (SJR) metric values journal citations based on the subject field, and the quality and reputation of the journal. The Source-Normalized Impact per Paper (SNIP) journal metric graph shows contextual citation impact by weighting citations based on the total number of citations in given subject area.
