PRISMA-P: Reporting Guideline for Systematic Review Protocols

Why a protocol needs its own reporting guideline

A registered, well-reported protocol lets other researchers, journal editors, and PROSPERO reviewers assess your planned methodology before you've started screening, which is precisely the point: it locks in your approach in advance and makes deviations visible later. A vague or incomplete protocol undermines that entire purpose, and PRISMA-P exists to specify exactly what a protocol needs to include for it to serve that function properly.

What PRISMA-P covers that PRISMA 2020 doesn't

The PRISMA-P checklist contains 17 items, organized into four sections that map closely to what you'd need before starting a review:

**Administrative information.** Title, registration details (including your intended PROSPERO number once assigned), author contact information, amendment history, and funding sources.

**Introduction.** Rationale for the review and your explicit objectives, framed using PICO or an equivalent structured question format.

**Methods.** This is the bulk of the checklist, and it's where PRISMA-P and PRISMA 2020 overlap most closely, though PRISMA-P frames everything prospectively: your eligibility criteria, planned information sources, a draft search strategy for at least one database, your planned study selection and data extraction processes, the data items you intend to collect, your planned risk-of-bias assessment approach, planned effect measures, and your planned synthesis methods, including how you'll handle heterogeneity if you're planning a meta-analysis.

**Meta-bias(es) and confidence in cumulative evidence.** Your planned approach to assessing reporting bias across studies, and if applicable, your planned approach to a GRADE or equivalent certainty assessment.

How this differs in practice from PRISMA 2020

The practical difference is tense and certainty. PRISMA 2020 asks what you did and what you found. PRISMA-P asks what you plan to do and why, before you know the answer. This means PRISMA-P items are inherently less specific in some places, since you can't report definitive results you don't have yet, but they still need to be concrete enough that a reader could judge whether your planned approach is sound.

A common gap: protocols that describe eligibility criteria and search strategy in reasonable depth, but leave the planned synthesis approach vague, something like "data will be synthesized appropriately," without specifying whether you plan a meta-analysis, what model you'd use if heterogeneity allows pooling, or what you'll do if it doesn't. This kind of vagueness is exactly what PROSPERO reviewers and PRISMA-P are designed to catch.

Using PRISMA-P alongside PROSPERO registration

PROSPERO's registration form and PRISMA-P's checklist cover substantially overlapping ground, since PROSPERO's 22-field form was itself designed with PRISMA-P in mind. Working through the PRISMA-P checklist before you open the PROSPERO registration form is a practical way to make sure you have every required field drafted and ready, rather than discovering gaps mid-submission.

Where protocols most often fall short

The most common weakness isn't a missing section, it's insufficient specificity within a present section: a search strategy described narratively rather than with an actual draft search string, or a synthesis plan that doesn't commit to fixed-effect versus random-effects reasoning in advance. PRISMA-P exists precisely to force these decisions into the open before screening begins, when it's still possible to catch and correct a methodological gap rather than defend one after the fact.

**[Get a quote](/systematic-reviews#prospero-registration)** for protocol development and PRISMA-P compliance support before you register.