Psychology advances knowledge by testing statistical hypotheses using empirical observations and data. The expectation is that most statistically significant findings can be replicated in new data and in new laboratories, but in practice many findings have replicated less often than expected, leading to claims of a replication crisis. We review recent methodological literature on questionable research practices, meta-analysis, and power analysis to explain the apparently high rates of failure to replicate. Psychologists can improve research practices to advance knowledge in ways that improve replicability. We recommend that researchers adopt open science conventions of preregi-stration and full disclosure and that replication efforts be based on multiple studies rather than on a single replication attempt. We call for more sophisticated power analyses, careful consideration of the various influences on effect sizes, and more complete disclosure of nonsignificant as well as statistically significant findings.

Psychological science is in the midst of what has been referred to as a “replication crisis.” The realization that many individual findings do not replicate in new studies has led to questioning the scientific method and the integrity of psychological science. We review the history of the replication crisis, and its positive and negative effects. Most of the elements of the replication crisis are re-emergent issues that methodologists have studied in the past, but to which researchers have become increasingly sensitized. Ultimately, we argue the value of the replication crisis, in that it has led to positive self-examination within our science and to the development of new and innovative methodology. The field is emerging from the replication crisis with a realization of the importance of multiple replication efforts, and an improved ethic of openness and transparency in the conduct of research.

This essay, written by the guest editor, is an introduction to a special issue of the Journal of Intelligence devoted to methodological issues associated with the Flynn Effect. The essay evaluates past Flynn Effect research in terms of exploratory versus confirmatory efforts. Future research is also cast within this same framework. Finally, the four special issue papers are briefly reviewed, including comments on their own exploratory/confirmatory status.