crossover design
A clinical trial methodology where participants receive multiple treatments in sequential periods, serving as their own controls.
Full Definition
A crossover design is a clinical trial structure where each participant receives two or more treatments in different time periods, with washout periods between treatments to eliminate carryover effects. This design is particularly valuable in psychiatric research because it controls for individual patient variability and requires smaller sample sizes than parallel-group studies. However, it requires careful consideration of treatment sequence effects, adequate washout periods, and is unsuitable for conditions where treatments have lasting effects or for studying progressive diseases.
Usage
Usage note: Distinguish from 'crossover' as a standalone term referring to treatment switching.
In Context
- "The study employed a double-blind, placebo-controlled crossover design with a two-week washout period." — Methods section
- "Period effects were assessed to ensure the crossover design assumptions were met." — Statistical analysis plan