Effectiveness of the “But-you-are-free” technique

Abstract

The “But you are free…” (BYAF) technique is a technique to increase compliance (for example, to give spare change for the bus), by adding the words “But you are free to accept or refuse” to the request. In this pre-registered meta-analysis, we examine the effect of the BYAF technique in 52 experiments (N = 19528). An analysis of 74 effect sizes showed a medium effect (g = 0.44, 95% confidence intervals (CI) [0.36, 0.51]) for the BYAF technique. A moderator analysis found a stronger effect for face-to-face interactivity over other types of interactivities. All the other moderators we used were not statistically significant. We did not find any differences between articles published before and after Carpenter’s (2013) meta-analysis. An examination of risk of bias showed that only seven studies were of “low risk”, and a meta-analysis of these studies showed no effect of the BYAF (g = 0.11, 95% CI [-0.18, 0.40]) We also found that most recent studies on the subject are too low-powered to detect the effect found by Carpenter (2013), and the reproducibility rates were critically low (R-index = 9.77%, Z-curve expected discovery rate = 6%). We propose some improvements to the design and experiments to ensure the effects found in the literature exist and are replicable. All materials are available on https://osf.io/8eqa5/