preregister

Preregister is the act of documenting and time-stamping a research plan before data collection or analysis begins. Preregistration is typically submitted to an online registry or repository and may include hypotheses, primary and secondary outcomes, population and sampling plan, data collection methods, and a prespecified analysis plan. The aim is to increase transparency, reduce researcher degrees of freedom, and deter practices such as p-hacking and HARKing (hypothesizing after results are known).

Common platforms for preregistration include the Open Science Framework (OSF), AsPredicted, and ClinicalTrials.gov, along with discipline-specific registries. Some preregistrations are linked to the registered report publication format, in which the study protocol is peer-reviewed before data collection and accepted in principle, with results reported later using the preregistered analyses.

Contents typically required or encouraged in a preregistration include the research questions or hypotheses, primary and secondary outcomes, planned sample size and power considerations, inclusion and exclusion criteria, data collection procedures, planned statistical analyses, and planned handling of missing data. Registrants may propose contingencies and specify whether exploratory analyses are allowed, and major deviations from the plan should be transparently documented and justified.

Impact and limitations: preregistration supports reproducibility and credibility but is not a guarantee against misconduct. It requires upfront planning and may constrain exploratory or exploratory-confirmatory research approaches. Adoption varies across disciplines, journals, and funding agencies, and not all preregistrations carry equal weight in publication or evaluation. Nevertheless, preregistration remains a key practice in the broader open science movement.