# Framing a systematic review research question with PICO

> Chapter 2 of 8 of The Systematic Review E-book by AIPRA. The research question is the first step of a systematic review and determines everything downstream. A strong question is specific, answerable, and scoped tightly enough to drive the search, screening criteria, and synthesis. Questions are normally anchored in a recognized framework: PICO (Population, Intervention, Comparison, Outcome) for quantitative clinical reviews, SPIDER for qualitative and mixed methods, PEO for exposures and experiences, and SPICE for social sciences.

- Source: https://aipra.co/systematic-review-ebook/research-question
- Topics: PICO framework; systematic review research question; PICO SPIDER PEO SPICE; systematic review question framework; rapid review vs systematic review
- Last updated: 2026-09-05
- Licence: free to read; cite as shown at the end of this file.

## Key points

- PICO (Population, Intervention, Comparison, Outcome) is the standard framework for quantitative clinical review questions.
- Alternative frameworks fit other review types: SPIDER for qualitative and mixed methods, PEO for exposures and experiences, SPICE for social sciences.
- The question framework also supplies your search concepts and later your inclusion and exclusion criteria, so framework choice is a methodological decision, not a formatting one.
- Plan for at least three reviewers: two screening and extracting independently, and a third to adjudicate disagreements.
- When screening and extraction are done by a single reviewer, the work is usually called a rapid review and is considered less methodologically rigorous than dual independent review with adjudication.

## Chapter outline

1. Why the research question comes first
2. Choosing a question framework (PICO, SPIDER, PEO, SPICE)
3. Building your team
4. Rapid reviews and single-reviewer workflows

## Questions this chapter answers

### What is the PICO framework?

PICO stands for Population, Intervention, Comparison, and Outcome. It is the most widely used structure for framing quantitative clinical systematic review questions, because each element maps directly onto search concepts and onto eligibility criteria used during screening.

### When should I use SPIDER instead of PICO?

SPIDER is generally preferred for qualitative and mixed-methods reviews, where an intervention and comparator may not exist in the way PICO assumes. PEO suits reviews about exposures and experiences, and SPICE is common in the social sciences.

### How many reviewers does a systematic review need?

Conventional practice is at least three people with relevant expertise: two who independently screen records and extract data, and a third who resolves conflicts. Independent duplicate assessment with adjudication is what makes screening decisions traceable and defensible.

### Is a rapid review the same as a systematic review?

No. A rapid review typically compresses or single-reviews stages such as screening and extraction to deliver results faster. It can be appropriate for time-critical decisions but is generally regarded as less methodologically rigorous than a full systematic review with dual independent review.

## How to cite this chapter

AIPRA. Framing a systematic review research question with PICO. In: The Systematic Review E-book. Updated 2026-09-05. Available from: https://aipra.co/systematic-review-ebook/research-question