Systematic Reviews

• Cochrane Handbook: Chapter 4: Searching for and Selecting Studies
• Finding Evidence for comparing Medical Interventions. (from the AHRQ and the Effective health Care Program)
• Search Strategy Checklist  (Medical Center Library, Duke University)
• PRESS - Peer Review of Electronic Search Strategies  (article with checklist - CADTH, Canada)
• A step-by-step guide to systematically identify all relevant animal studies.  Lab Anim. 2011 Oct 28. [Epub ahead of print]

A systematic review aims to include all relevant studies. Increasing the comprehensiveness (or sensitivity) of a search will reduce its precision and will retrieve more irrelevant articles. Recall (sensitivity) is defined as the number of relevant reports identified divided by the total number of relevant reports in existence. Precision (specificity) is defined as the number of relevant reports identified divided by the total number of reports identified. A thorough search takes time to develop and perform. Issues to consider in performing a comprehensive search:

• Inclusion of all concepts in the strategy
• Use of all appropriate subject headings
• Appropriate "exploding" of subject headings
• Appropriate use of subheadings
• Use of natural language (text words) in addition to controlled vocabulary terms
• Use of appropriate synonyms, acronyms, etc.
• Truncation and spelling variation as appropriate
• Appropriate use of limits, such as language, years, etc.
• Field searching, publication type, author, etc.
• Appropropriate use of Boolean operators
• Double-checking the correct combining of line numbers to eliminate "line errors"
• Adaptation of the search strategy for multiple databases