Double-Blind
A study design in which neither participants nor investigators know which treatment group participants are assigned to, minimizing expectation and assessment bias.
In Depth
Double-blinding is considered essential for rigorous clinical trials but is particularly challenging in cannabis research. THC's psychoactive effects make it difficult for participants to remain blinded — most can identify whether they received active treatment. This "unblinding" can inflate apparent treatment effects through expectation. Researchers have used active placebos (low-dose THC), expectancy manipulation, and crossover designs to address this. CBD trials face less blinding challenge due to its non-psychoactive nature.
Related Terms
More in Research Methods
Randomized Controlled Trial (RCT)
The gold standard study design in clinical research. Participants are randomly assigned to treatment or control groups to minimize bias and establish causation.
Systematic Review
A structured synthesis of all available evidence on a specific research question, using predefined criteria to identify, evaluate, and summarize studies.
Meta-Analysis
A statistical technique that combines quantitative data from multiple studies to produce a pooled estimate of effect size with greater statistical power than any individual study.
Placebo-Controlled
A study design in which the control group receives an inert substance (placebo) identical in appearance to the active treatment, to account for the placebo effect.
Observational Study
A study in which researchers observe participants without intervening. Includes cohort studies, case-control studies, and cross-sectional surveys.