Systematic literature reviews and meta-analyses: part 6 of a series on evaluation of scientific publications.
BACKGROUND
Because of the rising number of scientific publications, it is important to have a means of jointly summarizing and assessing different studies on a single topic. Systematic literature reviews, meta-analyses of published data, and meta-analyses of individual data (pooled reanalyses) are now being published with increasing frequency. We here describe the essential features of these methods and discuss their strengths and weaknesses.


METHODS
This article is based on a selective literature search. The different types of review and meta-analysis are described, the methods used in each are outlined so that they can be evaluated, and a checklist is given for the assessment of reviews and meta-analyses of scientific articles.


RESULTS
Systematic literature reviews provide an overview of the state of research on a given topic and enable an assessment of the quality of individual studies. They also allow the results of different studies to be evaluated together when these are inconsistent. Meta-analyses additionally allow calculation of pooled estimates of an effect. The different types of review and meta-analysis are discussed with examples from the literature on one particular topic.


CONCLUSIONS
Systematic literature reviews and meta-analyses enable the research findings and treatment effects obtained in different individual studies to be summed up and evaluated.
Ressing
Meike
M
Institut für Medizinische Biometrie, Epidemiologie und Informatik, Universitätsmedizin der Johannes Gutenberg-Universität Mainz, 55101 Mainz, Germany.
Blettner
Maria
M
Klug
Stefanie J
SJ
D004812:Epidemiologic Methods; D015201:Meta-Analysis as Topic; D010506:Periodicals as Topic; D012196:Review Literature as Topic; D012586:Science