Society has learned that there can be big pay-offs from science. Governments, private companies and funding agencies will therefore want to know whether their investments in research are well placed. As long as scientists ask for funding support, we must accept the right of these agencies to ask for proof of results. Within a department, the evaluation of performance may be one of several incentives for improving scientific quality and productivity. However, used alone, performance evaluation can lead to destructive competition and marginalization of potentially valuable staff members. Used in combination with research organisation and leadership, it may motivate many staff members. Results-based financing within a department should be used carefully. It should follow the setting of a clear research agenda, by the lowest-level leaders, and the organisation of the activity into groups. Only in groups with goals can the full potential of the staff in a department be mobilised to do more and better science.