A rapid review is an accelerated form of evidence synthesis that produces a defensible answer in weeks rather than months by streamlining, but not skipping, the systematic review method. Rapid reviews still report study selection with a PRISMA flow diagram, and the boxes are identical to a full review; what changes is that some steps are simplified, and those simplifications must be documented transparently. You can produce the flow diagram for a rapid review in our free PRISMA 2020 flow diagram generator exactly as you would for a full systematic review, then describe the methodological shortcuts in your methods section.
The defining principle of a credible rapid review is honesty about trade-offs. Speed is achieved by making explicit, pre-specified concessions in scope or process, and the reader must be able to see each one.
Where Rapid Reviews Streamline the Process
Rapid reviews accelerate the workflow at predictable points. Common, accepted shortcuts include:
- Restricting the search to fewer databases or a limited date range.
- Limiting language to English or another single language by design.
- Single-reviewer screening, sometimes with a second reviewer checking a sample rather than all records.
- Simplified or omitted formal quality grading, replaced by a briefer appraisal.
- Narrative synthesis instead of meta-analysis when time is short.
Each of these speeds the review but introduces a known limitation. The contrast with the full method is laid out in our guide on how to conduct a systematic review, and the value of a rapid review lies in choosing shortcuts deliberately rather than by omission.
The table below sets the two methods side by side so you can see exactly which steps a rapid review compresses and which it keeps intact.
| Step | Full systematic review | Rapid review |
|---|---|---|
| Timeline | Six months to two years | Two weeks to a few months |
| Databases searched | Several, plus grey literature and trial registers | Often two to three core databases |
| Date and language limits | Justified, usually broad | Pre-specified narrow limits accepted |
| Title and abstract screening | Two independent reviewers | One reviewer, second checks a sample |
| Full-text screening | Two independent reviewers | One reviewer, second verifies a sample |
| Data extraction | Dual, independent | Single, with a sample verified |
| Risk-of-bias appraisal | Full, dual assessment | Streamlined or single-reviewer |
| Synthesis | Meta-analysis where appropriate | Often narrative |
| PRISMA flow diagram | Required | Required, identical structure |
The Flow Diagram Stays, the Counts Stay Honest
A rapid review reports the same identification, screening, eligibility, and inclusion phases as any PRISMA diagram. The numbers must still reconcile top to bottom: records identified minus duplicates equals records screened, and so on. Choosing the right starting layout still matters, so our overview of the PRISMA 2020 flow diagram templates applies unchanged.
What differs is not the figure but the methods text beside it, which should state plainly how many databases were searched, the date and language limits, and how screening was divided between reviewers.
Documenting Single-Reviewer Screening
The most consequential rapid-review shortcut is screening by one reviewer. PRISMA does not forbid this, but it must be reported. Best practice is to:
- State that screening was conducted by a single reviewer.
- Describe any verification, such as a second reviewer checking a random sample of excluded records.
- Report the agreement on that sample if you measured it.
This keeps the flow diagram honest: the counts are real, and the reader knows the process that produced them. Our guide to systematic review screening best practices explains dual screening and agreement metrics, which help you decide how much verification a rapid timeline allows.
Reporting Standards and Methods Guidance
Rapid reviews have a growing methodological literature, and following it is what lets a reviewer or editor treat your shortcuts as principled rather than careless. The Cochrane Rapid Reviews Methods Group publishes recommended approaches that are now the most widely cited reference point, and its guidance is specific about where acceleration is acceptable. The group recommends, among other things, that you:
- Involve knowledge users early to keep the question tightly focused, since scope creep is what makes a rapid review slow.
- Limit the search to fewer databases but still document the full strategy so it is reproducible.
- Use single-reviewer screening with a second reviewer verifying a sample, commonly a fixed percentage of titles and abstracts or of excluded records, rather than dropping the second reviewer entirely.
- Extract data with one reviewer while a second checks a sample of extractions for accuracy.
- Conduct risk-of-bias assessment on included studies even when other steps are streamlined, because skipping appraisal altogether undermines the conclusions.
Alongside the method, the reporting convention is to use PRISMA as the backbone while clearly labelling the review as rapid. In practice this means:
- Calling the review a "rapid review" in the title and abstract.
- Using a PRISMA flow diagram for study selection, with the same four phases and the same reconciling counts as any review.
- Adding a short subsection that lists every deviation from a full systematic review and its rationale.
Transparency about deviations is what separates a respectable rapid review from a superficial one. A reader who can see precisely which corners were cut, and why, can judge the evidence on its merits; a reader left to guess will discount it.
When a Rapid Review Is the Wrong Choice
A rapid review suits a focused, time-sensitive question, such as informing a policy decision within weeks. It is a poor fit when the topic is broad, the stakes demand exhaustive searching, or a meta-analysis is essential. In those cases a full systematic review, or a continuously updated living systematic review, serves better. Matching the method to the question is the first decision, and the flow diagram simply documents whichever route you take.
Frequently Asked Questions
Do rapid reviews use a PRISMA flow diagram?
Yes. Rapid reviews report study selection with a standard PRISMA flow diagram. The figure is the same as a full review; the difference is that streamlined search and screening steps are documented in the methods.
Can one person screen in a rapid review?
Yes, single-reviewer screening is an accepted rapid-review shortcut. It should be reported explicitly, ideally with a second reviewer checking a sample of decisions to provide a verification estimate.
What is the difference between a rapid review and a systematic review?
Both follow the systematic review method, but a rapid review deliberately streamlines steps such as the number of databases searched, language limits, the number of screeners, and the depth of quality appraisal to deliver results faster. Each concession is pre-specified and reported.
How do I report shortcuts in a rapid review?
Add a methods subsection listing every deviation from a full review, such as databases omitted, date or language limits, single-reviewer screening, and any simplified appraisal, each with a brief rationale. Transparency about trade-offs is essential.
Is a rapid review less rigorous than a systematic review?
A rapid review accepts known limitations in exchange for speed, so it is narrower in scope, not necessarily lower in quality. When the shortcuts are pre-specified and clearly reported, a rapid review is a rigorous and legitimate form of evidence synthesis.