For information about any type of study design, check the Cochrane Glossary of Terms.

2.2.1 Randomised Controlled Trials (RCTs) and Controlled Clinical Trials (CCTs)

For Cochrane definitions and criteria for randomised controlled trials (RCTs) and controlled clinical trials (CCTs), check the Cochrane Handbook, Box 6.3.a: Cochrane definitions and criteria for randomised controlled trials (RCTs) and controlled clinical trials.

2.2.2 Controlled Before and After Studies (CBA) and Interrupted Time Series (ITS)

Some Groups also include these study designs in their registers. For definitions, see the Glossary of Terms on Cochrane.org. Some Review Groups such as the Effective Practice and Organisation of Care (EPOC) have particular expertise in identifying these types of studies; check with your Managing Editor (ME) whether your Group uses these types of studies, as it may be useful to contact groups such as EPOC for assistance in identifying them.

For information about CBAs, ITSs, and other forms of Non-Randomised Studies, check  The Cochrane Handbook, Box 13.1.a: Some types of NRS design used for evaluating the effects of interventions.

Some Groups add other reports to their registers that could be useful for their review authors. Examples are: systematic reviews, background papers, and other ‘non-trials’. Whether you do this depends on the policies of your editorial base. Please note: these types of reports should NOT be marked in the Cochrane Register of Studies (CRS) for publication to CENTRAL.