Sir

Your Editorial 'Unbalanced portfolio' (Nature 453, 1144; 2008) defends the scientific autonomy of researchers against pressure from bureaucrats seeking maximum economic returns. Although this position is admirable and likely to be popular among researchers, it might also be worth reflecting on our current situation.

Few scientists nowadays can afford to pursue research for science's sake, as suggested in the Editorial. Rather, most of us are trapped in a game of numbers, in which all our research output can be reduced to one or more of the following metrics: impact factors, average citations per article, total number of articles published, and the h-index.

This reductionist attitude towards scientific research has fostered an unhealthy research environment, evident in the copious examples of 'salami slicing' that litter scientific journals. Furthermore, the rules and significance of the game are all but opaque to the lay public (and to some members of our own profession), which alienates their interest in our investigations.

But our research is more relevant for them if it can be measured by its economic return. It would be hard to argue that the pressure to publish is somehow better or more meaningful than the pressure to recoup economic returns. Done properly, research assessment based on a balance between publications and economic output may be a way out of the impact-factor game.