Related Experiment Video
Updated: Oct 9, 2025

Inverse Probability of Treatment Weighting Propensity Score using the Military Health System Data Repository and National Death Index
Published on: January 8, 2020
Fooled by Randomness. The Misleading Effect of Treatment Crossover in Randomized Trials of Therapies with Marginal
Vicente Valentí1, Paula Jiménez-Fonseca2, Pavlos Msaouel3
1Medical Oncology Division, Hospital Sant Pau i Santa Tecla, Tarragona, Spain.
Abstract:
Crossover can bias clinical outcomes of randomized clinical trials by increasing the risk of both type I (false positive) and type II (false negative) errors. To show how crossover can increase type I error, we provide computer simulation and review herein illustrative examples (iniparib, olaratumab) of recently reported RCTs that demonstrated false-positive treatment efficacy signals due to crossover. The ethical issues associated with crossover are also discussed.
More Related Videos
Related Concept Videos
Crossover Experiments
Crossover designs are performed even with smaller sample sizes since the samples can act as their controls. These are better than simple randomized trials since patients are exposed to all the treatments.
Blinding
Bioequivalence Experimental Study Designs: Repeated Measures, Cross-Over, Carry-Over, and Latin Square Designs
Blind Procedures
The Placebo Effect
Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast,...

