CONSORT 2010 and Controversies Regarding Assessment of Blindness in RCTs

Blinding is one of the key design features of randomized clinical trials (RCTs). Studies not involving blinding could yield biased estimates of the effect of treatment. A meta-analysis found that double blind RCTs found 14% lower treatment effect on average than similar RCTs not described as double-blind. During past years many researchers have emphasized that more efforts are needed for blinding research. For example, sub-item 11b of the 2007 CONSORT statement suggested assessment of blinding. We were waiting for revision and extension of this item that would encourage people to collect and report more data and share their lessons. Yet disappointingly, it was eliminated from CONSORT 2010.As stated by the CONSORT authors, the rationale for this elimination was interpretational and measurement difficulties. Since the claim of internal validity for RCTs with a control arm rests on the assumption of appropriate blinding, we cannot afford to lose the CONSORT’s incentive for improvement and change. It seems contrary to an evidence-based approach to avoid obtaining data because we have to struggle with interpretation and measurement, which is common and natural in various scientific fields and problems.The philosophy of “let us give up because it is difficult to do or interpret” may not be well justified in professional scientific communities, especially when some reasonable statistical methods and clinical guidelines are available or can be developed.