Psychology has recently been viewed as facing a replication crisis because efforts to replicate past study findings frequently do not show the same result. Often, the first study showed a statistically significant result but the replication does not. Questions then arise about whether the first study results were false positives, and whether the replication study correctly indicates that there is truly no effect after all. This article suggests these so-called failures to replicate may not be failures at all, but rather are the result of low statistical power in single replication studies, and the result of failure to appreciate the need for multiple replications in order to have enough power to identify true effects. We provide examples of these power problems and suggest some solutions using Bayesian statistics and meta-analysis. Although the need for multiple replication studies may frustrate those who would prefer quick answers to psychology's alleged crisis, the large sample sizes typically needed to provide firm evidence will almost always require concerted efforts from multiple investigators. As a result, it remains to be seen how many of the recently claimed failures to replicate will be supported or instead may turn out to be artifacts of inadequate sample sizes and single study replications.

In this meta-analysis, the authors reviewed 105 studies on the relationships between racial discrimination and health outcomes among racial/ethnic minority Americans. The authors tested for moderator effects of measurement strategies, cultural factors, substance use, gender, and racial group differences. Findings indicate a statistically significant effect size between racial discrimination and health, with the largest effect for mental health and strongest for studies with multi-item measures.En este metaanálisis, los autores revisaron 105 estudios sobre las relaciones entre la discriminación racial y los resultados para la salud entre americanos pertenecientes a minorías raciales o étnicas. Los autores examinaron los efectos moderadores de las estrategias de medición, los factores culturales, el uso de sustancias, el género y las diferencias entre grupos raciales. Los hallazgos indican un efecto de tamaño estadísticamente significativo entre la discriminación racial y la salud, con el máximo efecto observado en la salud mental y el más fuerte en estudios con mediciones múltiples.Palabras clave: racismo, discriminación racial, salud, metaanálisis, minorías raciales o étnicas

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The rationale for insisting on properly designed studies is to ensure the construction of research literatures that are not influenced by biases of any sort. Once a literature is established, however, whatever answers it gives (usually via meta-analysis) are accepted as valid. The results of our favored statistical techniques are understood best when significant relationships are present while the meaning of null results are unclear. Thus, significant findings are more likely to be published. This file drawer problem has been known for many years. However, the effect that the file drawer has on research literatures has never been probed empirically. A new method is described that tests the impact a file drawer has on a research literature. The results of the file drawer on four separate psychological research literatures are presented.