New CONSORT and SPIRIT extensions for factorial trials

05 Dec 2023

Investigators at the MRC Clinical Trials Unit at UCL have published new guidelines on what to include in all trial protocols and published reports for factorial trials, in order to improve their transparency and utility.

Factorial trials are a special type of trial where each participant is assigned to more than one treatment, to facilitate multiple research questions being addressed in the same trial. They can help researchers to identify effective therapies more quickly, but problems in their design or analysis can make it difficult for researchers to understand a therapy’s benefit.

“Factorial trials offer researchers a more efficient way to test interventions, but the methods currently being used often lack transparency and may be at high risk of bias,” says first author  Brennan Kahan, Principal Research Fellow at the MRC CTU at UCL, who led the study. “Our research will help improve the utility of factorial trials by providing clear guidelines for reporting. By using this guidance, researchers can make their findings more widely interpretable and applicable.”

The SPIRIT 2013 and CONSORT 2010 statements provide checklists for protocols and reports of randomised trials, respectively. Today’s publications in JAMA and JAMA Network Open include SPIRIT-factorial, an extension to the SPIRIT 2013 Statement, and CONSORT-factorial, an extension to the CONSORT 2010 Statement, with detailed reporting requirements for factorial trials.   

Further information:

• CONSORT-factorial statement published in JAMA
• SPIRIT-factorial statement published in JAMA Network Open
• Invited commentary on the SPIRIT guidelines