Building Search Strategies

Search Strategy Fundamentals

A comprehensive search strategy is critical for identifying all relevant studies. The goal is to be sensitive (find all relevant studies) while maintaining reasonable precision (not overwhelming with irrelevant results).

Building Blocks Approach

Structure your search using the components of your PICO/PCC framework. Each component becomes a 'building block' of search terms combined with OR, then blocks are combined with AND.

  1. 1List all synonyms and related terms for each PICO component
  2. 2Combine synonyms within each component using OR
  3. 3Combine different components using AND
  4. 4Add study design filters if appropriate
  5. 5Test and refine based on known relevant articles

Example: Depression and CBT

Population (Depression): depression OR depressive disorder OR mood disorder

Intervention (CBT): cognitive behavioral therapy OR CBT OR cognitive therapy OR behavior therapy

Combined: (depression OR depressive disorder OR mood disorder) AND (cognitive behavioral therapy OR CBT OR cognitive therapy OR behavior therapy)

Boolean Operators

AND

Narrows results by requiring all terms to be present. Use between different concepts.

  • Example: diabetes AND exercise
  • Result: Articles must mention both diabetes and exercise

OR

Broadens results by requiring at least one term. Use for synonyms and related terms.

  • Example: elderly OR geriatric OR older adult
  • Result: Articles mentioning any of these terms

NOT

Excludes terms. Use cautiously as it may eliminate relevant studies.

  • Example: cancer NOT lung
  • Warning: May exclude relevant articles that mention both
  • Better to handle exclusions during screening phase

Advanced Search Techniques

Truncation (*)

Finds variations of a word stem.

  • Example: depress* finds depression, depressive, depressed
  • Example: child* finds child, children, childhood
  • Use carefully to avoid unintended matches (e.g., 'car*' matches cardiac, care, career)

Phrase Searching (" ")

Searches for exact phrases in order.

  • Example: "systematic review" ensures words appear together
  • Example: "quality of life" vs quality OR of OR life
  • Essential for multi-word concepts and proper names

Proximity Operators

Finds terms within a specified distance. Syntax varies by database.

  • PubMed: "cognitive therapy"[tiab:~3] (up to three words between the terms, in any order)
  • PubMed AND combines terms but does not set a distance between them
  • Embase: cognitive NEAR/3 therapy (within 3 words)
  • Useful for related concepts that may not be exact phrases

Field Tags and Limits

Restrict searches to specific fields to increase precision.

  • [TI] - Title only (most specific)
  • [TIAB] - Title and abstract (commonly used)
  • [MeSH] - MeSH terms only (see MeSH article)
  • [AU] - Author name
  • [DP] - Date of publication

Testing Your Search

  1. 1Identify 2-3 key articles you know should be included
  2. 2Run your search and verify these articles appear in results
  3. 3If key articles are missing, add relevant terms or broaden search
  4. 4Check precision: skim first 50-100 results for relevance
  5. 5Aim for 10-30% relevance rate (balance of sensitivity and precision)
  6. 6Document your search strategy including database, date, and results count

Database-Specific Considerations

Different databases require tailored strategies:

  • PubMed/MEDLINE: Use MeSH terms, automatic term mapping
  • Embase: Use Emtree terms, strong pharmaceutical coverage
  • CINAHL: Focus on nursing and allied health
  • PsycINFO: Comprehensive psychology and psychiatry
  • Cochrane Library: Pre-screened for trials, use for clinical questions
  • Web of Science: Broad coverage, citation tracking

During the Strategy phase, Scholara generates Boolean search strings translated for each database (PubMed, OpenAlex, Europe PMC, ClinicalTrials.gov) based on your PICO. You can edit the strings directly in the side drawer or ask the assistant to refine them in chat — for example, "add 'glycated hemoglobin' as a synonym" or "narrow the date range to 2015 onwards."

References