EBT uses “preregistration categories” to describe the extent to which authors have already seen study-relevant data while planning their methods (i.e. developing their study protocol). These categories are summarised in the table at the bottom of this page.
Authors indicate in their cover letter which preregistration level best reflects their relationship with existing data for their study. The handling editor makes the final decision as to the level.
At the stage of protocol review, information about prior sight of data is used by the editors and peer-reviewers to inform their comments on how potential bias could be described or reduced in the planned study. At the stage of final study, this information is used for contextualising findings.
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Our policy on preregistration categories is based on work by the Peer Community in Registered Reports and Lakens et al (2024).
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No one preregistration category is necessarily superior or better than another. Rather, the purpose of the preregistration categories is to help editors, peer-reviewers, and readers identify how prior sight of data could potentially have influenced the choice of methods and analyses being described in a study protocol that has been submitted to Evidence-Based Toxicology.
As an example, systematic reviews are typically a Category 0 or a Category 1 study. This is because SR authors will at least be familiar with the literature they are reviewing and will therefore have observed data relating to the key variables they are investigating, or may even have conducted previous SRs that analysed part of the data in detail.
Preregistered empirical studies that exclusively generate novel data are typically Category 6 studies, as it is impossible to observe or analyse data that does not exist before a study is conducted.
Generally speaking, authors submitting protocols for studies where they may have already accessed, observed, or analysed data or key variables for a planned study will be requested to (a) introduce methodological controls in their study to limit the impact that prior sight of data could have on how the study data are collected and analysed, and/or (b) articulate how prior sight of the data may be a limitation in the design and conduct of their study.
Preregistration categories derived from PCI Registered Reports (retrieved 10 October 2023, link) and Lakens et al. (2024).