Abstract

Background: Understanding is an important goal of the informed consent process in research. We sought to assess the interrater reliability (IRR) and concurrent validity of two measures of understanding in child and young adult subjects and their parents. Methods: We conducted a cross-sectional survey and interview-based study of children and young adults participating in a clinical trial for cancer, along with one parent per child or young adult subject. We estimated the IRR of the Semi-Structured Comprehension Interview (SSCI) and the MacArthur Competence Assessment Tool for Clinical Research (MacCAT-CR). We also estimated concordance between the SSCI, the MacCAT-CR, and the Quality of Informed Consent (QuIC). Results: For our sample of 32 subjects (16 parent–child pairs), IRR estimates were high for total score on the SSCI (intraclass correlation coefficient [ICC] = 0.88, 95% confidence interval [CI] = 0.76–0.94), as well as on the understanding (ICC = 0.93, 95% CI = 0.86–0.97) and reasoning (ICC = 0.97, 95% CI = 0.94–0.98) subscales of the MacCAT-CR. IRR was lower for the appreciation subscale of the MacCAT-CR (ICC = 0.70, 95% CI = 0.47–0.84). Scores on the SSCI were strongly correlated with scores on the understanding subscale of the MacCAT-CR (Spearman's rho = 0.72, 95% CI = 0.48–0.85) and the QuIC (Spearman's rho = 0.66, 95% CI = 0.24–0.87). Mean administration time for the SSCI was 3.1 minutes (95% CI = 2.7–3.5 minutes). Conclusions: The SSCI is a valid and reliable measure of understanding for use with both pediatric and adult research participants. It is easy to administer and score consistently, even by nonprofessional raters. The SSCI is a promising tool for use by clinician-investigators to study, detect, and correct deficiencies in understanding among children, adolescents, and adults making decisions about research participation.