TABLE 2.

Some advantages and disadvantages of systematic reviews.

Advantages.

A protocol for how the review will be conducted—written in advance—reduces the likelihood that ad hoc changes will be made that bias the outcomes. In cases where the protocol is published or otherwise shared with interested parties in advance of the actual review, stakeholders are thereby given the opportunity to recommend changes.

The incorporation of explicit criteria for including and excluding individual studies gives readers of the review a clear rationale for why some studies were included or excluded.

Assessing the risk of bias or broader methodological quality of the included studies gives reviewers and readers a sense of how much confidence to have in the review’s conclusions.

Reviews that assess certain studies as having a high risk of bias are likely to encourage the authors of those studies to improve the quality of their future research.

The explicit and transparent nature of the review process and its published review give readers a clear sense of how the review was carried out. This also enables interested parties to replicate the review, with or without making any protocol amendments deemed desirable.

Under certain conditions, data synthesis lends itself to meta-analysis, which provides a quantitative summary of the data from individual studies and overall.

Disadvantages.

Even once familiar with the process and tools, conducting a systematic review is still likely to take considerable time and labor. Review teams are likely to include, at a minimum, an information specialist, a systematic review “methodologist,” and subject-matter experts.

Although the basic framework for systematic reviews has remained the same across the fields to which it has been applied already, those seeking to apply this methodology to a new field will likely face some challenges not fully addressed by the experience gained in these other fields.