Choosing the Right Database for Your Question
Core summary
Different research tasks require different databases. A simple literature review might use PubMed alone, but a systematic review demands comprehensive multi-database searching. This lesson provides a decision framework.
Detailed explanation
Detailed explanation
Here is a practical decision framework for database selection: Quick clinical lookup (answering a bedside question): - Start with: PubMed or Cochrane Library - Goal: Find the best available evidence quickly - Minimum databases: 1 Narrative or scoping literature review: - Start with: PubMed + one additional database (Scopus or Web of Science) - Add Google Scholar for citation chasing - Minimum databases: 2 Systematic review or meta-analysis: - Mandatory: PubMed/MEDLINE + Embase + CENTRAL - Strongly recommended: At least one more (Scopus, Web of Science, CINAHL based on topic) - Grey literature: Trial registries, conference abstracts, preprints - Minimum databases: 3-4 (PRISMA recommends comprehensive searching) Drug/pharmacology research: - Must include: Embase (unique drug content) - Also search: PubMed, CENTRAL, International Pharmaceutical Abstracts Nursing or allied health research: - Must include: CINAHL - Also search: PubMed, Embase Psychology or behavioral research: - Must include: PsycINFO - Also search: PubMed, Scopus Documenting your database selection: Always state in your Methods section which databases you searched, the date range, and why you chose them. Reviewers and readers need this to assess comprehensiveness. A common beginner mistake is choosing databases based on convenience (what you have access to) rather than coverage. If your institution lacks access to Embase for a drug-related SR, you should note this as a limitation.
Clinical example
Dr. Khalid submits a systematic review on laparoscopic cholecystectomy techniques. The peer reviewer rejects it because he only searched PubMed. The reviewer notes: 'For a systematic review, searching a single database is insufficient. At minimum, CENTRAL and Embase should be searched per Cochrane Handbook recommendations.' Dr. Khalid learns an expensive lesson about database selection.
Research example
The Cochrane Handbook (Section 4.3) recommends searching at minimum CENTRAL, MEDLINE, and Embase for intervention reviews, plus subject-specific databases relevant to the review topic.
Knowledge check
Q1. What is the minimum number of databases recommended by Cochrane for a systematic review of interventions?
Q2. Why should database selection be documented in the Methods section?
Q3. What is a common beginner mistake in database selection?