Friday, August 19, 2011

Predictors of publication productivity: h-index

"Hirsch suggested that, for physicists, a value for h of about 10–12 might be a useful guideline for tenure decisions at major research universities. A value of about 18 could mean a full professorship, 15–20 could mean a fellowship in the American Physical Society, and 45 or higher could mean membership in the United States National Academy of Sciences.[3] Little systematic investigation has been made on how academic recognition correlates with h-index over different institutions, nations and fields of study."--Wikipedia.

In some scientific circles, the h-index is the summary figure of productivity. The h index combines the number of publications (h) that have been cited h times. if someone has published 10 papers cited 10 times, their index is 10. 11 papers each cited at least 11 times, the index is 11.

What's interesting to me is that there would be typical values for someone to be considered for the National Academy. Apparently the number is 45--45 papers cited at least 45 times.

One shouldn't get too hung up on metrics of scientific importance--they are too easily skewed and sliding scales are always necessary--but how does one get to 45? Publish a lot of papers? Start publishing early? Publish long? Or just write (or co-write) 45 great papers? 

I told myself I'd only spend 20 minutes on this, so I'll be brief.

I spent 20 minutes looking up h-index values for selected Academy members plus a few others and some early-career scientists (a few friends). In addition to h index, I calculated how long they had published, the number of papers published, and the most cited paper.

This is by no way scientific. Values can be off, etc.

Most of the national academy members were above 45. 

Of the three predictors, the best predictor of h index was number of publications. 

More work would probably blow this relationship apart, but one key take-home point would be to keep publishing, not worrying as much about the golden publication that'll be cited 1000 times. 

Back to real work....

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