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Replication Crisis

Reviewed by Psychology Today Staff

The replication crisis in psychology refers to concerns about the credibility of findings in psychological science. The term, which originated in the early 2010s, denotes that findings in behavioral science often cannot be replicated: Researchers do not obtain results comparable to the original, peer-reviewed study when repeating that study using similar procedures. For this reason, many scientists question the accuracy of published findings and now call for increased scrutiny of research practices in psychology.

What Led to the Replication Crisis in Psychology?
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Some scientists have warned for years that certain ways of collecting, analyzing, and reporting data, often referred to as questionable research practices, make it more likely that results will appear to be statistically meaningful even though they are not. Flawed study designs and a “publication bias” that favors confirmatory results are other longtime sources of concern.

A series of replication projects in the mid-2010s amplified these worries. In one major project, fewer than half of the studies that replicators tried to recreate yielded similar results, suggesting that at least some of the original findings were false positives.

A variety of findings have come into question following replication attempts, including well-known ones suggesting that certain types of priming, physical poses, and other simple interventions could affect behavior in surprising or beneficial ways. It is important to note that psychology is not alone, however: Other fields, such as cancer research and economics, have faced similar questions about methodological rigor.

The growing awareness of how research practices can lead to false positives has coincided with extreme instances of willful misrepresentation and falsification—resulting, in some cases, in the removal or resignation of prominent scientists.

When did the replication crisis start?

The field of psychology began to reckon with reproducibility around 2010 when a particularly dubious paper claimed to provide evidence of “precognition,” or the ability to perceive events in the future. Scientists increasingly began to discuss methodological concerns and to repeat experiments to corroborate published studies. The failure to consistently replicate those findings propelled the movement forward.

What research practices have led to unreliable results?

Journals are incentivized to publish interesting and surprising findings. This leads to publication bias, the tendency to publish positive findings rather than studies that find no effect. Researchers are incentivized to publish as often as possible to advance their careers. Therefore, they may exercise flexibility in their data analysis to achieve statistical significance.

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Understanding Research Methods
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To better grasp the replication crisis, it’s worth exploring some of the statistical methods used in psychology experiments. Flexibility in research methodology can help explain why researchers unconsciously (and sometimes consciously) produce unreliable results.

What is the null hypothesis?

When conducting an experiment, a researcher develops a hypothesis. For example, they may hypothesize that spending time with friends makes people happier. They then seek to reject the null hypothesis—the possibility that there is no association or effect of the sort the researchers propose. In this case, the null hypothesis would be that there is no relationship between happiness and spending time with friends.

What is statistical significance?

A finding is said to be statistically significant if the results of a study based on a particular sample of people are thought to be likely to generalize to the broader population of interest. A traditional benchmark of statistical significance in psychology is a p-value of .05, though more stringent benchmarks have recently been proposed.

How Psychology Is Moving Forward
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The replication crisis provoked heated internal debate in the field, with some arguing that it called for an overhaul of psychological science and others maintaining that the “crisis” was unreal or overblown. Nevertheless, psychologists interested in reform have pressed ahead with efforts to make the claims of psychological research more credible.

What needs to happen next?

The reformers’ immediate aims include greater transparency in the study planning and data analysis, more routine follow-up testing of results to make sure they can be reliably observed, and study designs that are well-suited to the scientific questions at hand. It remains to be seen which approaches will ultimately be most useful in increasing the veracity of psychological findings.

Which practices can fix the replication crisis?

Psychologists have developed an array of strategies to ensure that future findings have greater credibility. These include conducting more replications of emerging findings, relying on larger sample sizes, and leveraging thoroughly tested measures. Another is preregistration, delineating one’s hypothesis and study plans before conducting a study. Yet another is Registered Reports, in which journals agree to publish a transparently planned-out study no matter the results.

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