The Non-Randomised Studies Methods Group (NRSMG) of the Cochrane Collaboration advises the Steering Group to set policy and formulate guidance about the inclusion of non-randomized studies (NRS) of the effectiveness of healthcare interventions in Cochrane reviews.  Membership of the group is open to anyone who wishes to contribute actively to the work of group. The work of the group is primarily methodological, rather than focused on particular healthcare interventions.

Activities of NRSMG members include:

• developing guidelines to help decide when to include non-randomized data in Cochrane reviews;

• conducting methodological research in the use of non-randomized studies, including search methods, quality assessment, meta-analysis, pitfalls and misuse;

• conducting empirical research to compare bias in systematic reviews using both randomized and non-randomized studies, and to identify conditions under which randomized and non-randomized studies have led to similar conclusions, and situations in which the conclusions have been clearly contradictory;

• collating examples of healthcare questions that (a) have been studied using both non-randomized studies and randomized trials; and (b) have not been (or which for a long period have not been) studied adequately by means of randomized trials; and

• providing training at annual Cochrane Colloquia.