Systematic review - A review that uses explicit, systematic methods to collate and synthesize findings of studies that address a clearly formulated question.
Bias - A systematic deviation of a measurement from the 'true' value, leading to either an over-or underestimation of the treatment effect. Bias can originate from many different sources, such as errors in design and conduct of study. This may lead to selection bias (differences in comparison groups), performance bias (differences in care or exposure to factors other than the intervention of interest), measurement bias (differences in assessment of outcomes), etc.
Evidence-based medicine/healthcare (EBM) - The process of finding the most relevant research information in the medical literature to address a specific clinical problem. This evidence is then combined with clinical expertise and the patient values in making individual decisions. Evidence-based medicine involves the process of systematically finding, appraising and using recent research findings as the basis for clinical decisions. Systematic reviews provide powerful evidence to support all forms of EBM.
Level of Evidence - Study designs are often groups into a hierarchy according to their validity, or degree to which they are not susceptible to bias. The hierarchy indicates which studies should be given most weight in evaluation.
Meta-analysis - Results from several studies, identified in a systematic review, are combined and summarized quantitatively.
Randomized Controlled Trial - An experimental comparison study in which participants are allocated to treatment/intervention or control/placebo groups using a random mechanism. Participants have an equal chance of being allocated to an intervention or control group and therefore allocation bias is minimized (and virtually eliminated in very large studies).
Comparative Study - A study where the effect of an intervention or exposure is assessed using comparison groups. This can be a randomized controlled trial, a cohort study, a case-control study, etc.
Cochrane - An international non-profit organization that aims to help with informed decision making about healthcare by preparing, maintaining, and improving accessibility of systematic reviews & interventions. Cochrane seeks to help researchers and health professionals to make informed choices about treatment. The Cochrane Database of Systematic Reviews includes 4,650 reviews and 2,015 protocols available freely online (2017).
Joanna Briggs Institute- International nonprofit; based in South Australia. Primarily covers nursing topics and qualitative reviews. Offers training courses, workshops, and conferences online.
MeSH - Medical Subject Heading. Controlled vocabulary used in database searching to index citations (such as Medline).
Meta-analysis - A statistical technique for combining the results of a number of studies addressing the same question to produce a summary result.
Randomized Controlled Trial (RCT) - A comparative study with random allocation of subjects to interventions, and follow-up to examine differences in outcomes between the various groups.