A Problem in Theory and More: Measuring the Moderating Role of Culture in Many Labs 2

The multi-site replication study, Many Labs 2 (ML2), attempted to test whether population, site and setting variability moderates the likelihood of replication and effect size. The analysis concluded that sample location and setting did not substantially affect the replicability of findings. In this paper, we raise several issues with the ML2 approach to adjudicating the effect of culture that cast doubt on this conclusion. These theoretical and methodological problems (pre-registered at https://osf.io/6exr4) involve the: (1) selection of studies and sample sites for replication that are not theory-driven, (2) sampling of mostly WEIRD people around the world, (3) conflation of participants’ cultural backgrounds with the country where the samples came from, (4) use of the WEIRD backronym by decomposing it into a scale, and (5) application of a mean split of that WEIRD variable. Moreover, simulations reveal strikingly low statistical power for detecting cultural influences in a multi-side study designed like ML2. We propose methodologies to address problems (3) to( 5) by re-analyzing the ML2 dataset using an alternative approach. These results suggest that tackling only some of the design problems is insufficient to overcome the underlying theoretical and methodological deficiencies. We conclude with specific recommendations for assessing the role of population variability in future multi-site studies that address evidentiary value and effect size.