‘Statistically illiterate’ is how scientist and blogger Stephen Curry describes those who support impact factors, used to rank scientific journals. The impact factor, calculated annually, reflects the mean number of citations to articles published in a journal in the two preceding years.

He has a point. As Stephen describes:

….typically only 15% of the papers in a journal account for half the total citations. Therefore only this minority of the articles has more than the average number of citations denoted by the journal impact factor. Take a moment to think about what that means: the vast majority of the journal’s papers — fully 85% — have fewer citations than the average. The impact factor is a statistically indefensible indicator of journal performance; it flatters to deceive, distributing credit that has been earned by only a small fraction of its published papers.

In light of this, Stephen has started a call to arms of sorts, suggesting the start of a smear campaign to embarrass those who trumpet impact factors. So, he says, you can consider yourself statistically illiterate if you:

- include journal impact factors in the list of publications in your cv
- are judging grant or promotion applications and find yourself scanning the applicant’s publications, checking off the impact factors
- publish a journal that trumpets its impact factor in adverts or emails
- see someone else using impact factors and make no attempt at correction

I’m wondering if we need a boycott like that started against Elsevier?!

Oh, and speaking of statistically illiterate, the terrible use of statistics by biologists has long irritated me so a friend and I have been working on a smart phone app to help with this. Its in the final stages of development so watch this space!