What is Pre-registration?
Pre-registration is the practice of publicly specifying a study’s hypotheses, methods, and analysis plan before data collection begins. It prevents HARKing and p-hacking by creating a verifiable record of what was planned versus what was discovered.
How it works
A pre-registered study commits to specific hypotheses, sample size, outcome measures, exclusion criteria, and statistical tests before seeing any data. Deviations from the plan must be transparently reported as exploratory. This does not eliminate flexibility (researchers can still explore their data) but requires that exploration be labeled as such. Pre-registration platforms (OSF, AsPredicted, ClinicalTrials.gov) provide timestamped public records that prevent retroactive revision of plans to match results.
Applied example
A researcher pre-registers that they will test whether a gratitude intervention reduces depression scores on the PHQ-9, with 100 participants, using an independent samples t-test. If the result is non-significant but an unplanned analysis shows an effect on a different measure, the non-significant primary result must still be reported.
Why it matters
Pre-registration is the single most important methodological reform for reducing false positives in behavioral science, because it separates confirmatory from exploratory research.
