A systematic review is a comprehensive and authoritative summary of existing evidence on a specific issue or topic. It involves a detailed and comprehensive plan and search strategy derived a priori, with the goal of reducing biases and random errors. A systematic review extracts and interprets data from published studies on the topic, then analyzes, describes, critically appraises, and summarizes interpretations into a refined evidence-based conclusion. It is a way of summarizing and implementing evidence-based medicine. Systematic reviews may examine clinical tests, public health interventions, environmental interventions, social interventions, adverse effects, qualitative evidence syntheses, methodological reviews, policy reviews, and economic evaluations.
Some characteristics or features of systematic reviews include:
- They use explicit and reproducible methods to systematically search, critically appraise, and synthesize all available research that is relevant to a particular question.
- They are often required by research funders to establish the state of existing knowledge and are frequently used in guideline development.
- They are the most reliable source of evidence to guide clinical practice.
- They map areas of uncertainty and identify where little or no relevant research has been done, but where new studies are needed.
- They are a good way to make sense of large bodies of information and contribute to the answers to questions about what works and what doesnt.
Other types of reviews exist, such as scoping reviews, which are often used to categorize or group existing literature in a given field in terms of its nature, features, and volume. Rapid reviews are a form of evidence synthesis that may provide more timely information for decision making compared with standard systematic reviews.
