Objectives: Informed consent and understanding are essential ethical requirements for clinical trial participation. Traditional binary measures of understanding may be limited and not be the best measures of level of understanding. This study designed and compared 4 measures of understanding for potential participants being prepared for enrollment in South African HIV vaccine trials, using detailed operational scoring criteria.
Methods: Assessment of understanding of 7 key trial components was compared via self-report, checklist, vignettes, and narrative measures. Fifty-nine participants, including members of vaccine preparedness groups and 1 HIV vaccine trial, took part.
Results: There were significant differences across the measures for understanding of 5 components and for overall understanding. Highest scores were obtained on self-report and checklist measures, and lowest scores were obtained for vignettes and narrative descriptions.
Conclusions: The findings suggest that levels of measured understanding are dependent on the tools used. Forced-choice measures like checklists tend to yield higher scores than open-ended measures like narratives or vignettes. Consideration should be given to complementing checklists and self-reports with open-ended measures, particularly for critical trial concepts, where the consequences of misunderstanding are potentially severe.
From the *HIV AIDS Vaccines Ethics Group, School of Psychology, University of KwaZulu-Natal, Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa; and †HIV/AIDS Vaccine Division, Perinatal HIV Research Unit, Faculty of Health Sciences, University of the Witwatersrand, PO Box 114, Diepkloof, Johannesburg 1864, South Africa.
Received for publication May 18, 2006; accepted September 19, 2006.
Funding received from the South African AIDS Vaccine Initiative.
Reprints: Graham Lindegger, PhD, HIV/AIDS Vaccines Ethics Group, School of Psychology, University of KwaZulu-Natal, Private Bag X01, Scottsville 3209, South Africa (e-mail: firstname.lastname@example.org).