Understanding Impact Factor
In June of each year (or later, it just depends), Thomson-Reuters releases journal Impact Factors (IF) for the previous year. To many IF is a metric of quality that doesn’t make sense in the Social Sciences; to others, it’s how you get judged for publishing your research and counts towards tenure. IF is not a perfect metric, but it seems to be the one we are stuck with as the metric of record.
Let’s start with the ICA journal’s IF for 2011:
- Journal of Communication – 2.452
- Communication Theory – 1.476
- Human Communication Research – 1.836
- Journal of Computer-Mediated Communication – 2.172
How is this calculated? It’s surprisingly simple:
2011 IF = __Citations in 2011 to all items from 2009 and 2010___
Number of "substantive" items from 2009 and 2010
For Journal of Communication this came out to:
Got it? Easy. What this calculation does is show the average number of citations a journal gets in a 2-year timeline. This timeline is an artifact of IF’s original intention to measure in the physical sciences. For social sciences, this doesn’t make complete sense. The shelf life of social science research is greater. It doesn’t take into account the size of your discipline to journals in that discipline (one of the reasons you see higher IFs in broader disciplines like Psychology or Sociology and no where near what they are in the STM realm), it has no qualitative marker, and it can be manipulated by unethical practices.
After all of these flaws, it’s still the measure of record. Hiring and tenure get based on it, librarians look at it on whether to keep journals in their catalog, and publishers use it to sell packages with the highest “quality” of journals. There is an economy based on a number that was not developed to do this.
There are other measures, Eigenfactor and the ever expanding push for article level metrics fostered by PLoS One, but we will look to IF as our guiding number. For social science, however, I take more stock in the 5-Year-Impact Factor, and the ICA journals fare well in this metric too. The 5 year should be the standard to evaluate social science journals, it takes into account the longer shelf life of social science research.
Let us know how you feel about this in the comments section of the Wordpress version, and perhaps in London I’ll make this the theme of my session.