PICO Research Question Builder and Boolean Search String Generator
A focused question is the foundation of every systematic review, thesis and proposal. Fill in each element and its synonyms, and get a clear research question, a review title, inclusion criteria and ready-to-paste search strings for PubMed, Scopus and Web of Science.
How to use the PICO Research Question Builder
- Choose a framework: PICO for interventions, PEO for exposures and associations, SPIDER for qualitative questions or PCC for scoping reviews.
- For each element, type the main term and its synonyms, spelling variants and abbreviations, separated by commas. Use * for truncation (child* finds child, children, childhood).
- Untick “use in search” for elements you don’t want in the database search. Comparison and outcome are often left out to keep the search sensitive.
- Click Build to get the research question, a title, eligibility criteria and search strings for PubMed, Scopus, Web of Science and Google Scholar.
- Copy everything as a protocol draft, then refine it with your supervisor or a librarian and register it on PROSPERO or OSF.
Which question framework should I use?
| Framework | Stands for | Best for |
|---|---|---|
| PICO | Population, Intervention, Comparison, Outcome | Effects of treatments and interventions (most meta-analyses) |
| PICOS / PICOT | PICO + Study design / Time | When design or follow-up time defines eligibility |
| PEO | Population, Exposure, Outcome | Risk factors, associations, observational studies |
| SPIDER | Sample, Phenomenon of Interest, Design, Evaluation, Research type | Qualitative and mixed-methods evidence |
| PCC | Population, Concept, Context | Scoping reviews (JBI method) |
Tips for a strong search string
- Synonyms are the key to sensitivity. Include spelling variants (behaviour/behavior), abbreviations (T2DM) and older terms.
- Use truncation carefully.
therap*finds therapy, therapies and therapeutic, butcat*also finds catalogue. - Add controlled vocabulary. Combine free-text terms with MeSH in PubMed (for example
"Diabetes Mellitus, Type 2"[MeSH]) and Emtree in Embase. - Do not search every element. Outcomes are often reported inconsistently in abstracts, so leaving them out avoids missing studies.
- Record everything. PRISMA 2020 asks for the full search strategy for every database. Our PRISMA flow diagram generator helps you report what happened next.
Frequently asked questions
What is a PICO question?
A PICO question breaks a clinical or research question into four parts: Population, Intervention, Comparison and Outcome. For example: ‘In adults with type 2 diabetes (P), does aerobic exercise (I), compared with usual care (C), improve HbA1c (O)?’
Can I use PICO outside medicine?
Yes. PICO works for any intervention question: agriculture (P = wheat under drought, I = bacterial inoculation), education (P = students, I = AI tutors) or engineering. For non-intervention questions, use PEO or PCC.
Should the comparison and outcome be in my search string?
Usually not. Many good studies do not mention the comparator or the exact outcome in the title or abstract, so including them can make you miss studies. Search for population and intervention, then screen for C and O.
Why does PubMed use [tiab]?
[tiab] limits a term to the title and abstract fields, which keeps the search focused. Add MeSH terms as well to catch articles indexed with controlled vocabulary.
Is this search string ready for my systematic review?
It is a strong first draft. Test it in each database, check that it finds known key papers, add controlled vocabulary and ideally ask an information specialist to peer review it (the PRESS checklist).
Is my question saved or shared?
No. Everything stays in your browser and nothing is sent to a server.
