Systematic Reviews and Meta-Analysis:The Best Evidence by Combining Data from Several Studies

The practice of evidence based medicine is the integration of individual clinical expertise with the best available external clinical evidence from systematic research and patient’s values and expectations. We need evidence for both clinical practice and for public health decision making. The evidence come from good reviews which is a state-of-the-art synthesis of current evidence on a given research question. Given the explosion of medical literature, and the fact that time is always scarce, review articles play a vital role in decision-making in evidence based medical practice. Given that most clinicians and public health professionals do not have the time to track down all the original articles, critically read them, and obtain the evidence they need for their questions, therefore, systematic reviews and clinical practice guidelines may be their best source of evidence. Hence, the objective of this article is to introduce readers to the concept of systematic reviews and meta-analysis, outlining why they are important, describing their methods and terminologies used and thereby helping readers with the skills to recognize and understand a reliable review.