Concealed Allocation and Open-Label Assessment Were Different Features of REVELIO
REVELIO plans concealed random allocation but open-label driving assessment. Concealing the upcoming assignment during enrollment is different from keeping participants and assessors unaware of treatment afterward.
The allocation procedure has a defined role
The protocol describes pre-randomized allocation cards drawn by a team member not involved in screening. Screening personnel cannot access the cards before assignment. This helps protect the assignment process from being influenced by knowledge of which group a participant would enter.
Later awareness remains part of the design
Group assignment is disclosed on the study day, and participants, personnel and outcome assessors are not blinded. The authors cite the perceptible psychoactive effects of THC as a challenge to placebo blinding. Participants remain unaware of their measured THC concentrations and pre-driving performance-test results, which is a narrower form of withheld information.
Interpret each safeguard separately
Randomization and concealment do not remove all possible expectancy or observer influences after disclosure. Likewise, the open-label design does not mean the allocation was nonrandom. This protocol supplies no completed detector-accuracy result. Its value is a transparent account of which forms of bias the investigators plan to address and which conditions remain. Future claims should describe those features accurately rather than labeling the whole study simply blinded or unblinded without qualification.
Related analysis: the source’s broader findings and limitations.
