Short Answer
PROSPERO (International Prospective Register of Systematic Reviews) is a free and mandatory database in which you must register your systematic review protocol before the literature search. Administered by the University of York, it has held more than 200,000 review records since 2011.
The registration must be prospective: retrospective registrations made after the search is completed are considered unreliable by editors, and most high-impact journals require the term "prospective registration." Mandatory fields include the research question in PICO format, inclusion/exclusion criteria, the list of databases, the quality assessment tool (RoB 2, NOS, QUADAS-2), and the meta-analysis plan. On successful registration, an ID is issued in the CRD42026XXXXXXX format, and this ID must be reported in the methodology section of the manuscript. As a team running PROSPERO-registered systematic reviews (Hip OA CRD420261324092, Knee OA CRD420261298163) and with a research infrastructure that has produced a publication in an international peer-reviewed journal, Serteser Consulting provides end-to-end support in PICO framing, completing the methodology section, and amendment processes.
Registering with PROSPERO before you start writing your systematic review is no longer optional; for the vast majority of high-impact journals it is a requirement. So how does this process work?
What Is PROSPERO and Why Is It Needed?
PROSPERO (International Prospective Register of Systematic Reviews) is a free database run within the University of York. It has held more than 200,000 systematic review records since 2011.
A PROSPERO registration serves two main functions:
Certificate of originality: It shows that someone else is not answering the same question at the same time. When you submit to a journal, it preempts the objection that "this topic has already been studied."
Methodological transparency: The fact that the methodology cannot be changed after the analysis is done, meaning the method is not chosen by looking at the results, increases scientific reliability.
When Should You Register?
Before you begin the literature search. Ideally, right after the PICO question is finalized.
Registration made after the search has been performed, or even after some studies have been reviewed, is not accepted, or is found unreliable by editors.
Step-by-Step PROSPERO Registration
1. Create an account
prospero.york.ac.uk → Register → Open an account with your email and institutional details.
2. Start a new registration
"Start a new review" → Select the systematic review type (Intervention, Diagnostic, Prevalence, etc.)
3. Fill in the basic information
Review title: Should be clear and informative. For example: "Artificial Intelligence in Knee Osteoarthritis Diagnosis: A Systematic Review"
Review question: A single sentence in PICO format. For example: "In adult patients with knee osteoarthritis (P), does AI-based diagnosis (I) compared to radiologist assessment (C) improve diagnostic accuracy (O)?"
Condition or domain being studied: ICD codes can be used.
Participants: Characteristics of the population to be included
Intervention(s): Intervention(s) and comparison
Main outcome(s): Primary outcome(s)
4. Methodology section
Searches: Which databases will be searched? Is there a time restriction? A language restriction?
Study designs: Which study designs will be included?
Data extraction: Who will do it? How will disagreements be resolved?
Risk of bias: Which tool will be used? (RoB 2, NOS, QUADAS-2, etc.)
Data synthesis: Will a meta-analysis be performed? Which software? How will heterogeneity be assessed?
5. Team information
The name and institution of all researchers. Registration can be done without a second researcher, but the journal may require two independent searches.
6. Register and obtain your ID
When registration is completed, you are given an ID in the CRD42024XXXXXXX format. This ID must be written into the manuscript.
Common Mistakes
"Let's start and register later": Not accepted. The registration must be prospective.
Leaving the PICO question vague: Vague PICO → vague inclusion criteria → weak review.
Skipping the methodology section: Writing "To be confirmed" and moving on is the most common mistake. Fill it in with as much detail as possible.
Choosing the wrong review type: An intervention review and a diagnostic review are different. The choice determines the quality assessment tool.
For support with systematic review methodology, including PROSPERO registration, request a free consultation.
Where Do People Get Stuck Most in This Process?
- You cannot fill in the "Data synthesis" section of the PROSPERO form because it is not yet clear whether you will perform a meta-analysis.
- After registering, there was a change in the protocol, and it is unclear how to make an amendment.
- You chose the wrong review type (intervention vs diagnostic), and you do not know whether it is possible to go back.
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