Consent Comprehension in the 21st Century: What is Missing?

Because federal regulations and ethical guidelines emphasize the importance to subjects of understanding informed consent, many experimental interventions have been tested in hopes of improving subject comprehension. But most consent comprehension studies have not been psychometrically sound, producing inconsistent results because they are missing measurable definitions of comprehension, adequate validity and reliability, standardized test administration, and scoring and interpretation issues—as well as the practicality of using such tests in clinical research settings. As proxy measures for comprehension, readability recommendations to write consent forms at a sixth-eighth grade reading level have not successfully increased informed consent comprehension either. The increasing complexity of clinical trials in the 21st century may make it impossible to substantially improve comprehension tests unless researchers include those psychometric issues that have been largely ignored and better understand what can and cannot be accomplished by naive readability recommendations.