Open-Label Trial

An open-label trial is a clinical trial design where there is no blinding or masking implemented, and investigators and trial subjects are aware of the treatment allocation.

Open label trials do not have to involve randomization or include a control treatment. Open trials may be used to compare the efficacy of two similar interventions or in trials where blinding is not feasible or possible- surgical intervention, device trials. Open label trials are avoided whenever possible due to the increased risk of introducing bias that may distort the results.

Source: Sedgwick, P. (2014). What is an open label trial? BMJ, 348(may23 1), g3434.