Impact factors and bias

Journals’ impact factors are not as important as they used to be. Nevertheless I found an intersting parer on publication bias by Marcus Mufano (with a stress on the last o I think). He has lots of interesting papers, here is his homepage

Even without getting into the details the graphs tell a surprising story. A genetic link has been established so we can tell when a paper is reporting data that are biased. The intersting thing is that the bias gets stronger the higher the impact factor of the journal. Possibly people are trying too hard to sell their findings and make them appear exciting.

This interpretation is consistent with the fact that publication bias is also stronger for authors based in the US compared to Europe. Perhaps a consequence of the greater pressure in the US to publish the super paper that will make one’s career (and lead to tenure). If so, putting pressure on academics may be good for getting lots of publications out of them but it may be bad for science.


Munafò, M.R., Matheson, I.J. & Flint, J. (2007). Association of the DRD2 Taq1 polymorphism and alcoholism: A meta-analysis of case-control studies and evidence of publication bias. Molecular Psychiatry, 12, 454-461.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s