Definition: The practice of publishing the plan for a study, including research questions/hypotheses, research design, data analysis before the data has been collected or examined. It is also possible to preregister secondary data analyses (Merten & Krypotos, 2019). A preregistration document is time-stamped and typically registered with an independent party (e.g., a repository) so that it can be publicly shared with others (possibly after an embargo period). Preregistration provides a transparent documentation of what was planned at a certain time point, and allows third parties to assess what changes may have occurred afterwards. The more detailed a preregistration is, the better third parties can assess these changes and with that the validity of the performed analyses. Preregistration aims to clearly distinguish confirmatory from exploratory research.

Related terms: Confirmation bias, Confirmatory analyses, Exploratory Data Analysis, HARKing, Pre-analysis plan, Questionable Research Practices or Questionable Reporting Practices (QRPs), Registered Report, Research Protocol, Transparency

References: Haven and van Grootel (2019), Lewandowsky and Bishop (2016), Merten and Krypotos (2019), Navarro (2020), Nosek et al. (2018), & Simmons et al. (2021)

Drafted and Reviewed by: Mahmoud Elsherif, Gisela H. Govaart, Helena Hartmann, Tina Lonsdorf, William Ngiam, Eike Mark Rinke, Lisa Spitzer, Olmo van den Akker, Flávio Azevedo

Note that we are currently working on an automated mechanism to link references cited above with their full-length version that can be found at with all references used so far.