[Overviews - status quo, potentials and perspectives]

The increase in scientific literature has led reviewers to conduct overviews, hereby creating a new publication type. Overviews of reviews may have several advantages. For example, they can be conducted in a shorter time frame, they offer the opportunity of providing decision makers with a broader summary of the evidence, allowing comparison of multiple treatments, and they can be helpful in investigating discordant findings from multiple systematic reviews. However, there are some specific characteristics concerning methodology in conducting overviews. Questions that arise are how to deal with overlapping reviews, how the quality of the included reviews should be assessed, how discordant results should be dealt with, whether and how additional searches for current primary studies should be conducted. Overviews of reviews often lack methodological rigour. Methodological standards and reporting guidelines for overviews are needed to improve the quality of this new publication type.