preregistration

Preregistration is the practice of documenting a study’s hypotheses, design, and analysis plan in a time-stamped, publicly accessible document before data collection begins. The main aim is to increase research transparency and credibility by separating confirmatory, hypothesis-testing analyses from exploratory analyses, which are more prone to bias and data-driven decisions.

A preregistration typically specifies the research questions or hypotheses, primary and secondary outcomes, sample size, inclusion criteria, data collection procedures, and the planned statistical methods. It may also outline data handling, stopping rules, and how deviations will be justified. Preregistrations are hosted on registries or platforms such as ClinicalTrials.gov for clinical trials, ISRCTN, and the Open Science Framework (OSF) Preregistration. Some registries allow embargoing details until publication.

Preregistration is related to, but distinct from, registered reports. In registered reports, the study protocol is peer-reviewed before data collection, and in-principle acceptance for publication can be granted based on the soundness of the methods rather than results. Preregistration focuses on declaring plans upfront, with subsequent results following that plan unless deviations are justified.

Impact and limitations: preregistration has been widely adopted in clinical research and growingly in psychology and the social sciences to curb questionable research practices such as p-hacking and HARKing. It does not guarantee valid results, and plans may be adjusted with transparent justification. Critics note potential rigidity and administrative burden, and some exploratory work may still be valuable if clearly labeled as such. Overall, preregistration is a tool to enhance transparency and reproducibility in research.