Biomedical research funding: when the game gets tough, winners start to play.

Extramural funding provides major support for biomedical research in academia, and National Institutes of Health (NIH) grants often constitute direct evaluation criteria for promotions and tenure. Therefore, NIH budget trends influence long-term scientific strategies and career decisions, as well as the progress of science itself. Our analysis of the last 37 years of NIH awards, however, reveals that the success rate of grant applications submitted for funding is negatively related to the total yearly amount of (inflation-adjusted) NIH extramural expenditure. Instead, as might be expected, the ratio between available funding and the number of submission directly predicts the probability of winning support in any given year. We purport that the considerable success rate variability can be parsimoniously explained by a proportional but delayed reaction of the number of applications to budget fluctuations. As a counterintuitive consequence, grant proposals conceived during lean periods might stand the best chance of success.