This study explores the criteria by which biologists in the United Sta
tes evaluate their peers' scientific performance. Six distinguished bi
ology professors rated forty-two former National Science Foundation Po
stdoctoral Fellows on the basis of the latter's CVs and bibliographies
. The most powerful predictor of these quality judgements was the rate
d scientist's annual productivity rate: this explained more than 40% o
f the variance in the evaluators' judgements.