What is PCC? Framing scoping review questions,explained through PICO

PCC stands for three elements.

P (Population/Participants): whose research are you collecting? C (Concept): what is the research about—the intervention, phenomenon, or method at the center. C (Context): in what setting, region, or situation?

For example: "Research on telerehabilitation (Concept) for older adults (Population) in home-care settings (Context)"—that sentence is the shape of a scoping review question.

Line PCC up against PICO and you'll notice the missing C for Comparison. That's no accident.

PICO is a framework for answering a question—"Is intervention A more effective than comparator B?" PCC is a framework for mapping—"What research exists in this area?" There's no comparison because the review isn't judging which option wins. That's where the two philosophies part ways.

You can tell whether your review calls for PICO or PCC by phrasing it as a question.

If you want to know "Does it work?" or "Which is better?", that's PICO—systematic review territory. If you want to know "What has been studied, and how much?" or "What methods are in use?", that's PCC—scoping review territory. If the shape of the question and the type of review don't match, you will get stuck midway—guaranteed. When in doubt, check with your supervisor at this stage.

Of the three PCC elements, beginners most often stall on Concept. Population and Context are relatively easy to define concretely; Concept tends to come out either too broad or too narrow.

The trick is to draw the boundary between research that belongs on your map and research that doesn't. Take "telerehabilitation": does it include instruction over video calls? App-guided self-training? Spelling out that boundary in advance dramatically reduces the churn during screening later.

Once the PCC is settled, both the search and the selection criteria fall out of it.

Search terms come from combining synonyms for the Population, Concept, and Context. Selection criteria start from the principle "include studies matching all PCC elements," with added conditions for year, language, and study type. PCC is both the frame for your question and the blueprint for the entire review.

Because a scoping review deliberately collects broadly, the reference count balloons. The moment of real danger arrives when hundreds of PDFs and classification notes start scattering across folders and files.

Paperfy gives each paper a single page with its AI summary, figures, tables, and original PDF, and the summary is editable. Add classification notes there—"P: older adults / Concept: telerehabilitation (video instruction) / Context: home care"—and your map material accumulates on the paper's own page. Need to check the basis for a classification? The original text is on the same page.

Once your question is framed with PCC, the next steps are searching, charting, and identifying gaps. The whole scoping review process is covered in our guide to scoping review methods (https://paperfy.app/en/articles/scoping-review-method)—read on from there.