Quality science from quality measurement: The role of measurement type with respect to replication and effect size magnitude in psychological research.

Diana E Kornbrot,Richard Wiseman,George J Georgiou,Sergi Lozano

doi:10.1371/journal.pone.0192808

Abstract

The quality of psychological studies is currently a major concern. The Many Labs Project (MLP) and the Open-Science-Collaboration (OSC) have collected key data on replicability and statistical effect sizes. We build on this work by investigating the role played by three measurement types: ratings, proportions and unbounded (measures without conceptual upper limits, e.g. time). Both replicability and effect sizes are dependent on the amount of variability due to extraneous factors. We predicted that the role of such extraneous factors might depend on measurement type, and would be greatest for ratings, intermediate for proportions and least for unbounded. Our results support this conjecture. OSC replication rates for unbounded, 43% and proportion 40% combined are reliably higher than those for ratings at 20% (effect size, w = .20). MLP replication rates for the original studies are: proportion = .74, ratings = .40 (effect size w = .33). Original effect sizes (Cohen’s d) are highest for: unbounded OSC cognitive = 1.45, OSC social = .90); next for proportions (OSC cognitive = 1.01, OSC social = .84, MLP = .82); and lowest for ratings (OSC social = .64, MLP = .31). These findings are of key importance to scientific methodology and design, even if the reasons for their occurrence are still at the level of conjecture.

Highlights

There has been much recent concern about the reproducibility of research in science. In psychology this has led to two major replication studies
There were 36% of OSC and 72% of MLP effects that replicated
For the MLP, the proportion replication rate is 74% compared to 40% for ratings

Summary

Introduction

There has been much recent concern about the reproducibility of research in science In psychology this has led to two major replication studies. The Open Science Collaboration (OSC) attempted to replicate 100 cognitive and social psychological effects from prestige cognitive, social and general psychological journals (2). The OSC attempted one replication of each of 98 originally significant effects. The Many Labs Project [4] made 36 attempts to replicate 16 effects from 13 studies, mostly in social psychology journals (1).

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Results

Conclusion