Repeated investigations of the same phenomenon typically yield effect sizes that vary more
than one would expect from sampling error alone. Such variation is even found in exact …

Effect sizes are underappreciated and often misinterpreted—the most common mistakes
being to describe them in ways that are uninformative (eg, using arbitrary standards) or …

Replication is often viewed as the demarcation between science and nonscience. However,
contrary to the commonly held view, we show that in the current (selective) publication …

Statistical practice in psychological science is undergoing reform which is reflected in part by
strong recommendations for reporting and interpreting effect sizes and their confidence …

Statistical power depends on the size of the effect of interest. However, effect sizes are rarely
fixed in psychological research: Study design choices, such as the operationalization of the …

The increased use of effect sizes in single studies and meta-analyses raises new questions
about statistical inference. Choice of an effect-size index can have a substantial impact on …

Effect sizes are the currency of psychological research. They quantify the results of a study to
answer the research question and are used to calculate statistical power. The interpretation …

Psychology is undergoing a replication crisis. The discussion surrounding this crisis has
centered on mistrust of previous findings. Researchers planning replication studies often …

Can recent failures to replicate psychological research be explained by typical magnitudes
of statistical power, bias or heterogeneity? A large survey of 12,065 estimated effect sizes …

The present article presents a tutorial on how to estimate and interpret various effect sizes.
The 5th edition of the Publication Manual of the American Psychological Association (2001) …