Measurement of scientific productivity is difficult. The measures used (impact factor of the journal, citations to the paper being measured) are crude. But these measures are now so universally adopted that they determine most things that matter: tenure or unemployment, a postdoctoral grant or none, success or failure. As a result, scientists have been forced to downgrade their primary aim from making discoveries to publishing as many papers as possible—and trying to work them into high impact factor journals. Consequently, scientific (...) behaviour has become distorted and the utility, quality and objectivity of articles has deteriorated. Changes to the way scientists are assessed are urgently needed, and I suggest some here. (shrink)