Preregistration: Definition, advantages, disadvantages, and how it can help against questionable research practices

Questionable research practices (QRPs), such as p-hacking (i.e., the inappropriate manipulation of data analysis to find statistical significance) and post hoc hypothesizing, are threats to the replicability of research findings. One key solution to the problem of QRPs is preregistration. This refers to time-stamped documentation that describes the methodology and statistical analyses of a study before the data are collected or inspected. As such, readers of the study’s report can evaluate whether the described research is in line with the planned methods and analyses or whether there are deviations from these (e.g., analyses performed so that the research hypotheses is confirmed). Here, we aim to describe what preregistration entails and why it is useful for psychology research. In this vein, we present the key elements of a sufficient preregistration file, its advantages as well as its disadvantages, and why preregistration is a key, yet partially insufficient, solution against QRPs. By the end of this chapter, we hope that readers are convinced that there is little reason not to preregister their research.