Same data, different analysts: variation in effect sizes due to analytical decisions in ecology and evolutionary biology

Even when using the same data, researchers can reach very different conclusions because of the choices they make in analyzing it. In a study with 174 teams, analyses of Blue Tits and Eucalyptus trees showed wide variation in results. Some effects were strong, some weak, and some opposite to the average trend. These differences weren’t explained by the methods or peer reviews used. The study…