This is an archived version of the Handbook. For the current version, please go to or search for this chapter here.  What is in The Cochrane Central Register of Controlled Trials (CENTRAL) from Specialized Registers of Cochrane Review Groups and Fields?

It is an ‘essential core function’ of CRGs that their "editorial bases develop and maintain a Specialized Register, containing all relevant studies in their area of interest, and submit this to CENTRAL on a quarterly basis", as outlined in Section ‘Core functions of Cochrane Review Groups’ in The Cochrane Manual (


The Specialized Register serves to ensure that individual review authors within the CRG have easy and reliable access to trials relevant to their review topic, normally through their Trials Search Co-ordinator. CRGs use the methods described in this chapter of the Handbook to identify trials for their Specialized Registers. Most CRGs also have systems in place to ensure that any additional eligible reports identified by authors for their review(s) are contributed to the CRG’s Specialized Register. The registers are, in turn, submitted for inclusion in CENTRAL on a quarterly basis. Thus, records included in the Specialized Register of one CRG become accessible to all other CRGs through CENTRAL. Many Fields also develop subject-specific Specialized Registers and submit them for inclusion in CENTRAL as described above. To identify records in CENTRAL from within a specific Specialized Register it is possible to search on the Specialized Register tag, such as SR-STROKE. A list of all the Specialized Register tags can be found in the ‘Appendix: Review Group or Field/Network Specialized Register Codes’ in the ‘CENTRAL Creation Details’ Help File in The Cochrane Library:



Records in a CRG’s Specialized Register will often contain coding and other information not included in CENTRAL, so the Trials Search Co-ordinator will often be able to identify additional records in their Specialized Register, which could not be identified by searching in CENTRAL, by searching for these codes in the Specialized Register. Conversely, the search functionality of the bibliographic or other software used to manage Specialized Registers is usually less sophisticated than the search functionality available in The Cochrane Library so a search of CENTRAL will retrieve records from the Specialized Register that may not be easily retrievable from within the Specialized Register itself. It is therefore recommended that both CENTRAL and the Specialized Register itself are searched separately to maximize retrieval.