Groups that can potentially be blinded in RCTs

ParticipantsIndividuals who are randomly assigned to the interventions being evaluated
Healthcare providersThe physicians, nurses, physiotherapists, or other personnel who care for the participants during the study period or those who administer the interventions
Data collectorsIndividuals who collect data for the study outcomes; data collection could include administering a questionnaire, taking a physical measurement, or eliciting symptoms
Judicial assessors of outcomesThe individuals who ultimately decide whether a participant has had the outcome, or outcomes, of interest
Data analystsThe individuals who conduct the data analysis
Data safety and monitoring committeeThe committee that reviews the data to advise on the continuing safety of the trial and persistent uncertainty of the efficacy of the intervention being evaluated
Manuscript writersThe individuals who write versions of the manuscript before the breaking of the randomisation code: in a fully blinded study, one version is written with the assumption that group A received the experimental intervention, and the other is written with the assumption that group B received the experimental intervention