What is a Systematic Review?
A systematic review is a summary of the medical literature that uses explicit methods to perform a comprehensive literature search and critical appraisal of individual studies and that uses appropriate statistical techniques to combine these valid studies. (CEBM).
Key characteristics of a systematic review are:
- a clearly stated set of objectives with pre-defined eligibility criteria for studies
- an explicit, reproducible methodology
- a systematic search that attempts to identify all studies that would meet the eligibility criteria
- an assessment of the validity of the findings of the included studies, for example through the assessment of risk of bias
- a systematic presentation, and synthesis, of the characteristics and findings of the included studies. (Cochrane Handbook for Systematic Reviews of Interventions, 2008, p. 6)
Meta analysis is a systematic review that uses quantitative methods to synthesize and summarize the results.
Similiarities and Differences Between Systematic and Literature Reviews
Reproduced from: Bettany-Saltikov, J. (2010). Learning how to undertake a systematic review: Part 1. Nursing Standard, 24(40): 47-55.
|Systematic Review||Literature Review|
|Question||Focused on a single question||Not necessarily focused on a single question, but may describe an overview|
|Protocol||A peer review protocol or plan is included||No protocol is included|
|Background||Both provide summaries of the available literature on a topic|
|Objectives||Clear objectives are identified||Objectives may or may not be identified|
|Inclusion and Exclusion Criteria||Criteria stated before the review is conducted||Criteria not specified|
|Search Strategy||Comprehensive search conducted in a systematic way||Strategy not explicitly stated|
|Process of Selecting Articles||Usually clear and explicit||Not described in a literature review|
|Process of Evaluating Articles||Comprehensive evaluation of study quality||Evaluation of study quality may or may not be included|
|Process of Extracting Relevant Information||Usually clear and specific||Not clear or explicit|
|Results and Data Synthesis||Clear summaries of studies based on high quality evidence||Summary based on studies where the quality of the articles may not be specified. May also be influenced by the reviewer's theories, needs and beliefs|
|Discussion||Written by an expert or group of experts with a detailed and well grounded knowledge of the issues|
How to Books
Provides practical guidance for undertaking evidence synthesis based on a thorough understanding of systematic review methodology. It presents the core principles of systematic reviewing, and in complementary chapters, highlights issues that are specific to reviews of clinical tests, public health interventions, adverse effects, and economic evaluations.
A guide to the development, implementation and evaluation of clinical practice guidelines.