Systematic review
A structured synthesis of research that uses explicit, reproducible methods to locate, assess, and summarize studies addressing a focused question.
PICO framework: A framework that structures clinical questions around population, intervention, comparator, and outcome. It helps turn a broad topic into an answerable review question.
Eligibility criteria: Predefined rules specifying which people, studies, or records qualify for inclusion in a research project. They define which studies can answer the review question.
Scoping review: A review that maps the scope, characteristics, and gaps in research on a broad topic. It maps a field rather than typically estimating an answer to a focused question.
Cochrane: An international organization that produces and supports systematic reviews of health evidence. Its review groups and methods have helped establish standards for health evidence synthesis.
Research waste: Research effort or outputs that fail to answer relevant questions or provide usable evidence. Poorly chosen or reported studies can leave reviews unable to resolve decision-relevant questions.
Protocol (science): A prespecified plan describing a study’s questions, methods, and analyses. A review protocol records planned methods before results can influence them.
Study selection: The process of screening records and deciding which studies meet predefined eligibility criteria. Screening applies the review’s eligibility rules to search results.
Narrative review: A scholarly overview of research that does not necessarily use comprehensive, prespecified methods. Its flexible selection and synthesis differ from a systematic review’s explicit procedures.
Evidence-based medicine: The integration of research evidence, clinical expertise, and patient values in medical decisions. Systematic reviews summarize research evidence used alongside clinical judgment and patient preferences.
Selective outcome reporting: The preferential reporting of some measured outcomes over others, often based on their results. Missing outcomes can bias a synthesis even when included studies are found.