The National Academy of Medicine, the Cochrane Handbook for Systematic Reviews of Interventions, and the Agency for Healthcare Research and Quality each recommend securing the services of a librarian to plan strategically effective and comprehensive searches:
Levels of Research Evidence
Systematic reviews are considered the highest form of evidence as they are an accumulation of research on one topic. Cochrane Systematic Reviews are considered the most rigorous systematic reviews being done.
|Features||Narrative Literature Review||Systematic Literature Review|
|Source||Not usually specified, potentially biased||Comprehensive sources and search approach explicitly specified|
|Selection||Not usually specified, potentially biased||Uniformly applied preselected inclusion/exclusion criteria|
|Evaluation||Variable||Rigorous critical evaluation|
|Synthesis||Often qualitative, quantitative through meta-analysis*||Often qualitative, quantitative through meta-analysis*|
Steps for a Systematic Review
Green, S., & Higgins, J. P. T. (editors). (2011). Chapter 2: Preparing a Cochrane review. In J. P. T. Higgins, & S. Green (Eds.). Cochrane Handbook for Systematic Reviews of Interventions (Version 5.1.0). Available from http://handbook.cochrane.org
Meta-Analysis. (2008). In W. A. Darity, Jr. (Ed.), International Encyclopedia of the Social Sciences (2nd ed., Vol. 5, pp. 104-105). Detroit: Macmillan Reference USA.