PICO stands for Population, Intervention/Comparison, and Outcome — the core elements used to define the scope of a systematic review. Rayyan uses AI to automatically identify and highlight PICO-related terms within article abstracts and extract them into filterable facets in the Filters panel.
How to activate PICO
Go to the Screening stage or the Review data tab and click PICO in the toolbar. Rayyan will process your references — this may take a few moments. Alternatively, open the Filters panel and click Extract PICO inside one of the PICO facets.
Once extraction is complete, highlighted terms appear in abstracts and the PICO facets in the Filters panel are populated. PICO does not appear automatically on reviews created before the feature was enabled on the owner's account — trigger extraction manually using the PICO button.
How PICO highlighting works
Once activated, Rayyan highlights detected PICO terms directly in article abstracts. Each PICO element has a distinct color and meaning:
| PICO element | What it means | Highlight color |
|---|---|---|
| P — Population | Who is being studied — the patient group, population, or problem | Purple |
| I — Intervention | What is being applied, tested, or exposed — a drug, treatment, or procedure | Blue |
| C — Comparison | What the intervention is compared against — a placebo, control group, or alternative | Blue |
| O — Outcome | What is being measured, improved, or assessed | Orange |
Hover over any highlighted term to see which PICO element it is associated with and its confidence percentage. PICO highlighting is contextual — it only highlights text the AI determines is relevant to a PICO element, not every instance of a word. You can turn highlighting on or off at any time using the Highlights toggle in Review Settings without losing your extracted PICO data.
How PICO filtering works
Once extraction is complete, three PICO facets appear in the Filters panel: PICO Population, PICO Intervention/Comparison, and PICO Outcome. Each shows detected terms with the number of references containing them, sorted by frequency. The Intervention/Comparison facet combines both I and C — control groups, placebos, and comparators all appear here.
Rayyan uses truncated word forms in PICO facets (e.g., "pediatr" instead of "pediatric") to capture term variations and maximize coverage. The same OR/AND filter logic that applies to all facets applies here: multiple selections within one PICO facet use OR logic; selections across different facets use AND logic.
Continue to: How to Use Data Sampling in Rayyan