A review of several independent trials that have shown a plant’s efficacy. This is the highest level of clinical evidence and several meta-analyses provide the most reliable information. It assesses the quality of trials and statistically analyzes those that are deemed methodologically sound for efficacy.
A quantitative method of combining the results of independent studies meeting specified protocol criteria (usually drawn from the published literature) and synthesizing summaries and conclusions that may be used to evaluate therapeutic effectiveness and plan new studies.
A statistical procedure to combine the results from many studies to give a single estimate, giving weight to large studies.
A research method which entails taking several studies on a given topic and analyzing those studies together, thus making a large study out of them. The method is of relatively recent development, and much attention is being given to improving the methodology itself. The study resulting using meta-analysis is also called a “meta-analysis.”
A method used by researchers to try to bring together related published (and sometimes unpublished) studies dealing with similar treatments or similar disorders. The process starts with trials as the basis of collecting information. A search of the medical literature will reveal all such related trials which can then be analyzed and combined in a systematic review. In this way, it is possible to try to obtain more accurate results than might be possible in a single trial, especially if it involved only a small number of patients. Such reviews can then be re-evaluated and re-analyzed to deal with such problems as biased initial recruitment or faulty statistical analysis, in an attempt to refine the results. This procedure is described as meta-analysis. The technique is used increasingly in medicine, with the cochrane collaboration in the forefront of systematically reviewing and storing clinical and research data to provide a reliable information base on which to take forward the practice of evidence-based medicine.
The combination of data from several different research studies to gain a better overview of a topic than what was available in any single investigation. Data obtained from combined studies must be comparable and compatible for a meta-analysis to reach logical conclusions.
A type of research review that uses statistical techniques to analyze results from a collection of individual studies.