The Centre for Reviews and Dissemination (CRD) is an international center engaged exclusively in evidence synthesis in the health field. The CRD also manages a number of databases that are used extensively by health professionals, policy makers and researchers around the world. The CRD also undertakes methods research and produces internationally accepted guidelines for undertaking systematic reviews.

The Database of Abstracts of Reviews of Effects (DARE): CRD researchers systematically search the world literature to identify and describe systematic reviews, appraise their quality and highlight strengths and weaknesses.

Extensive search strategies are run on a weekly basis and assess thousands of citations to identify potential systematic reviews.

Those citations identified as potential systematic reviews are then independently assessed for inclusion by two researchers using the following criteria:

1. Were inclusion/exclusion criteria reported?
2. Was the search adequate?
3. Were the included studies synthesized?
4. Was the quality of the included studies assessed?
5. Are sufficient details about the individual included studies presented?

To be included, reviews must meet at least four criteria.