| For effective communication of risk/benefit information, it is important to ensure that the recipient understands probabilistic information. Comprehension may be influenced by whether the format in which probabilistic information is presented (i.e., numeric versus verbal) matches people's format preferences. An experimental design was used to explore this problem in the context of mammography screening.; A convenience sample of 180 women aged 25–45 years with no history of breast cancer and mammography received pre-assembled randomized packages, containing a breast health information pamphlet and four questionnaires, in either verbal or numeric format. The questionnaires assessed women's comprehension and self-reported intention to use screening mammography. “Match” (n = 95) and “mismatch” (n = 85) subgroups emerged based on whether or not the received format was congruent with women's preferences.; There was no significant match/mismatch subgroup difference in mean overall comprehension scores. However, the mean comprehension score was lower in those who received numeric but preferred verbal than in those who received and preferred verbal format (16 vs. 44, F = 19.50; p < 0.001). Among the women who received the numeric format, overall comprehension was related to educational level; the mean comprehension score was lower for those with ≤grade 13 than those with higher education (17 vs. 42, t = 4.64; p = 0.001).; There was no significant match/mismatch subgroup difference in intention to use screening mammography. Women who intended to seek screening reported higher: overall baseline knowledge of breast cancer/screening (OR = 1.26; CI = 1.13, 1.40); perceived risk of encountering breast cancer (OR = 3.35; CI = 1.19, 9.46); and perceived usefulness of information (OR = 7.56; CI = 2.40, 23.89).; This study is unique in targeting younger women and revealing limited breast cancer knowledge in this group. The results indicate that comprehension of probabilistic information may be associated with format preference, particularly when information is communicated quantitatively. The results also imply that systematic investigation is needed to characterize the relationships among format preferences, various types of numeracy problems, and strategies for communicating information that foster satisfactory levels of comprehension. Finally, the study design could guide future exploratory investigations regarding risk perception, comprehension, and decision formation in other screening programs. |
