Keywords and Synonyms

The keyword generation process follows three steps: Step 1 — Decompose your PICO into concepts. Not every PICO element needs to be searched. Usually you search P (population) and I (intervention or exposure). Adding C (comparator) and O (outcome) may over-restrict your results. Example PICO: In patients with type 2 diabetes (P), does metformin (I) compared to sulfonylureas (C) reduce cardiovascular mortality (O)? Search concepts: (1) Type 2 diabetes, (2) Metformin. Start with these two. Step 2 — Generate synonyms for each concept. Researchers use different words for the same thing. Your search must capture all variations: - Type 2 diabetes: diabetes mellitus type 2, T2DM, type II diabetes, NIDDM, non-insulin dependent diabetes, adult onset diabetes - Metformin: Glucophage, dimethylbiguanide, metformin hydrochloride Sources for synonyms: MeSH entry terms, Emtree terms, published systematic reviews on your topic (check their search strategies), Wikipedia medical pages, textbook indexes, and clinical guidelines. Step 3 — Consider truncation and wildcards. Most databases allow truncation (e.g., 'diabet*' finds diabetes, diabetic, diabetics) and wildcards (e.g., 'p?ediatric' finds both pediatric and paediatric). A common mistake is using too few synonyms, which misses studies using different terminology. Another mistake is using too many concepts, which over-restricts the search and excludes relevant papers.