PROSPERO is the international prospective register of systematic reviews, hosted by the University of York's Centre for Reviews and Dissemination. Registering a review means depositing its planned methods, the research question, eligibility criteria, search strategy, and outcomes, on a public record before screening and data extraction begin. That timestamp is the whole point: it lets readers see what you intended to do, so any later departure from the plan is visible rather than hidden.
Registration is quick relative to the review itself, and it has become an expectation rather than an optional extra for health-related reviews. Many journals now ask for a registration number before they will consider a manuscript.
What registration actually protects against
A pre-registered protocol guards against two specific problems. The first is outcome switching, where a team quietly promotes a secondary outcome to primary because it produced a more striking result; with the original plan on public record, that switch is detectable. The second is duplication: before starting, you can search PROSPERO to see whether an identical review is already underway, sparing months of redundant effort. Both protections depend on registering early, while the methods are still genuinely prospective.
These benefits sit alongside, not instead of, writing a full protocol. The register captures a structured summary; the PRISMA-P guided protocol holds the detailed methods. You typically draft the protocol first and use it to populate the registration form.
What you submit
The form asks for the core elements of the planned review, most of which you will already have if your question and protocol are written.
| Registration field | What it captures |
|---|---|
| Review question | Usually framed with PICO |
| Eligibility criteria | Population, intervention, comparison, outcomes, designs |
| Search strategy | Databases and approach you will use |
| Outcomes | Primary and secondary, named in advance |
| Data and analysis plan | Extraction and synthesis methods |
| Timeline and team | Anticipated dates and reviewer roles |
Because these fields mirror the protocol, the registration itself is mostly transcription rather than fresh writing. The harder intellectual work, defining a clean question and defensible eligibility criteria, happens before you ever open the form.
Cost, timing, and whether it is required
PROSPERO is free to use. After you submit, the team runs a basic editorial check for scope and completeness, and registration is typically issued within a few weeks, though timing varies with submission volume. It is not a peer review of your methods, only a check that the record is eligible and complete.
Whether registration is mandatory depends on who is asking. PROSPERO itself does not compel anyone, but many journals, funders, and degree programmes now require a registration number, so in practice it is effectively expected for most health-related systematic reviews. Reviews far outside health, or purely methodological reviews, may fall outside its scope and use a different registry or the Open Science Framework instead.
Where registration sits in the workflow
Registration belongs near the start, right after the protocol and before the search. It does not replace any later step: you still search comprehensively, screen in duplicate, and report transparently. When the review is finished, the registration number appears in the manuscript and lets readers compare what you planned with what you did. For the surrounding steps, see the complete systematic review process, and when you reach the reporting stage you can build the diagram with our PRISMA 2020 flow diagram tool.
Frequently Asked Questions
What is PROSPERO registration?
PROSPERO registration is the act of recording a systematic review's planned methods on the international prospective register hosted by the University of York before the review's results are known. It captures the question, eligibility criteria, search strategy, and outcomes, creating a public, time-stamped record that improves transparency and lets readers detect any later departures from the plan.
Is registering with PROSPERO free?
Yes. PROSPERO is a free service. There is no charge to submit a registration or to search existing records. After submission, the editorial team performs a basic check for eligibility and completeness before the record is published with a registration number.
Is PROSPERO registration mandatory for a systematic review?
PROSPERO itself does not force anyone to register, but registration is increasingly required by journals, funders, and academic programmes, so it is effectively expected for most health-related systematic reviews. Registering also helps you avoid duplicating a review already in progress, which is a practical reason to do it even where no rule demands it.
How long does it take to register on PROSPERO?
Completing the form takes a short time if your protocol is already written, since the fields mirror the protocol. After submission, the editorial check and publication of the record typically take a few weeks, though the exact wait depends on current submission volume. Registering early, before screening starts, preserves the prospective value of the record.