Crossover Design
A clinical trial design in which participants receive both the active treatment and control at different time points, with each participant serving as their own control.
In Depth
Crossover designs are common in cannabis research because they reduce the sample size needed (each participant provides data for both conditions) and control for individual differences in cannabis response. Key considerations include adequate washout periods between treatment phases (to prevent carryover effects) and order effects (whether receiving treatment first vs. second affects outcomes). THC's long half-life in chronic users requires washout periods of at least 2–4 weeks.
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.