What is a protocol?
A review protocol is a document that describes the plan for your review before you begin, and is key to ensuring the integrity, transparency, and rigor of the review process. It outlines your review question, objectives, methods, eligibility criteria, search strategy, and planned approach to data extraction and analysis.
Creating a protocol before starting your review helps ensure your methods are transparent, consistent, and reproducible. It also reduces the risk of introducing bias by making important methodological decisions in advance.
If you’re new to writing protocols, Covidence offers two free guides:
What is a registered protocol?
A registered protocol is a review protocol that has been publicly recorded in an online registry or repository before the review is conducted. Registering a protocol:
promotes transparency in the review process
helps prevent unnecessary duplication of reviews
provides a public record of your planned methods
makes it easier for readers to identify and understand any changes made during the review
Not all review types require protocol registration. Whether you should register your protocol depends on your review type, research discipline, and any requirements from your institution, funder, or target journal. For example, registration is common for many health-related systematic reviews, while protocols for other types of reviews may instead be shared through an open repository or published alongside the completed review.
Common protocol registries
PROSPERO
PROSPERO is an international registry for prospectively registered systematic reviews with health-related outcomes, including healthcare, public health, education, crime, justice, and social welfare. It also accepts rapid reviews and umbrella reviews.
Open Science Framework (OSF)
OSF is a free, open platform that supports protocol registration for many research disciplines and review types, including systematic and scoping reviews.
INPLASY
INPLASY is an international registry for systematic review and meta-analysis protocols across a broad range of disciplines. It also accepts scoping review protocols and typically publishes registrations within 48 hours.
Figshare
Figshare is an online repository where researchers can publicly share research outputs, including review protocols. Protocols receive a persistent DOI, making them easy to cite.
Research Registry
Research Registry is a registry for a wide range of research studies, including systematic review protocols.
Protocols.io
protocols.io is an open platform for sharing detailed research protocols. It supports versioning, collaboration, and public publication of protocols, allowing researchers to update protocols as methods evolve.
Organizations
The Campbell Collaboration maintains a register of systematic review titles and publishes reviews once they reach the protocol stage.
The Joanna Briggs Institute (JBI) registers systematic review protocols conducted through its organisation. Protocols listed on their site may already be published or may be in preparation for publication within six months of registration.