Are published techniques for increasing service-gratuities/tips effective? P-curving and R-indexing the evidence

Recently developed statistical tools are used to assess the evidential value and replicability of the published experimental literature on ways to increase tips. Significantly right-skewed full and half p-curves indicate that the literature is more than a collection of Type 1 errors - it provides evidence of real effects. Moreover, those real effects are scattered across both replicated and non-replicated effects as well as across the work of each of the major contributors to this literature. An overall r-index of 0.55 indicates that over half of the reported effects would likely be replicated if the studies were repeated. More research is need to ascertain the reliability of specific effects - especially those reported by Gueguen, because lower power makes his effects less replicable than others in the literature. Nevertheless, readers can be reasonably confident that most of the techniques for increasing tips in this literature will work.