a review on the review studies within the health domain

review studies are those researches in which the population under study consists of original articles in a defined field of human knowledge. the aim of the present review article is to overview such review studies and to determine the advantages and disadvantages of each study within the health domain. at the end of 2012 the pub med search engine was searched using “ systematic reviews ” and “ meta-analyses ” terms, which should appear in the title plus “ methodology ” term that should appear either in the title or the abstract of the papers. then by changing the search methods plus studying the references of the retrieved papers the scope of search was complete. given the necessity and importance of review studies, the style of doing them has been substantially changed during time and they improved from traditional reviews into s ystematic reviews and then meta-analyses from published data. individual participant data meta-analysis and prospectively planned pooled analysis are two new studies that are recently introduced. by knowing the pros and cons of review studies and their applications one might get the most of such studies within the health domain.