When peer reviewers are suggested by a paper's author(s), the feedback is likely to be more positive than when the journal editors chose the reviewers. That may not be surprising, but a new study published in PLoS ONE has found evidence of this occurring even when an open peer review system is used. The journal looked at was Atmospheric Chemistry and Physics, published by Copernicus Publications on behalf of the European Geosciences Union. On Nature's The Great Beyond blog the paper's author, Lutz Bornmann, based at the Max Planck Society in Berlin, said: "The danger is really that an author suggested their best friends. Alternatively – and more charitably – the reviewers selected by authors could be in a better position to know a good result in their field when they see one, compared to those selected by journal editors."