Reading versus comprehension: implications for patient education and consent in an outpatient oncology clinic

Written educational materials and consent forms are often given to patients with little regard for their ability to read them. Nationwide sampling and data from the 1990 census suggest that 10% of U.S. adults are functionally illiterate. In this study, 100 adult patients (64 female, 36 male) seen consecutively in an oncology clinic were tested for reading vocabulary (RD-VOCAB) and reading comprehension (RD-COMP) using the Woodcock-Johnson Psychoeducational Battery. The mean grade levels of education (last grade completed), reading vocabulary, and reading comprehension of all participants were 12.5, 11.3, and 10.5, respectively. The discrepancy between the grade level of education and RD-COMP varied by age, the largest discrepancies being found in the 30-39 (three grades) and 60-69 (2 1/2 grades) age groups. After controlling for educational level, it was found that the mean grade level of RD-COMP was statistically lower than educational level. Statistically assuming all subjects to have completed high school, the mean levels of RD-COMP ranged from ninth grade in the 30-39 age group to twelfth grade in the 40-49 age group. This study underscores the fact that the health professional cannot assume that a patient who has completed a certain grade level in school can read at the corresponding level. Consent forms and other health education materials should be written at least three grade levels lower than the average educational level of the target population.