Maximal positive controls: A method for estimating the largest plausible effect size

Effect sizes in social psychology are generally not large and are limited by error variance in manipulation and measurement. Effect sizes exceeding these limits are implausible and should be viewed with skepticism. Maximal positive controls, experimental conditions that should show an obvious and predictable effect, can provide estimates of the upper limits of plausible effect sizes on a measure. In this work, maximal positive controls are conducted for three measures of aggressive cognition, and the effect sizes obtained are compared to studies found through systematic review. Questions are raised regarding the plausibility of certain reports with effect sizes comparable to, or in excess of, the effect sizes found in maximal positive controls. Maximal positive controls may provide a means to identify implausible study results at lower cost than direct replication.