Editorial: Sweet nothings - the value of negative findings for scientific progress.

It is well-known that selective outcome reporting and publication distort the information that is made publicly available, and so undermine the reliability of what we consider evidence-based knowledge. Perhaps less known is that the risk of bias extends beyond the process of reporting and publishing results. Two further sources of bias are spin and selective citing. Spin relates to selective interpretation, meant to transform a basically negative conclusion into a more positively toned one; citation bias is the phenomenon that positive findings tend to be cited more than negative ones. The effects of these sources of imbalance accumulate, and the consequences can be huge. This issue of JCPP contains several articles with wholly or partly negative findings, which hopefully will be cited frequently. Publications regarding negative findings comprise an underrepresented and often undervalued minority, and therefore deserve all the support they can get.