First, the sizes of the denominators were manipulated within subjects and had four levels (see Table 1). Second, the selleck Wortmannin provision of icon arrays was manipulated between subjects and had two levels: icons in addition to the numerical information about risk reduction (see Figure 1), and no icon arrays (i.e., numerical information only). Finally, language was a between-subjects factor and had two levels: information about treatment risk reduction was provided either in participants’ native language, Polish, or in a nonnative language, English. Participants’ estimates of treatment risk reduction were measured following the procedure used by Schwartz et al. [10].Results in this study were consistent with those reviewed above (see Figures 3(a) and 3(b)).

When information about the drug was provided numerically and the sizes of the denominators were different, many participants provided inaccurate estimates of treatment risk reduction. Again, a tendency to focus on absolute numbers in numerators instead of taking proportions into account (i.e., denominator neglect) can account for these patterns of inaccurate estimates. Importantly, this tendency was particularly pronounced when the information was provided in English rather than in Polish. Furthermore, when the sizes of the denominators were equal or when they were different and icon arrays were added to the numerical information, denominator neglect was significantly reduced. This increase in accuracy was more prominent when information about treatment risk reduction was not provided in participants’ native language, presumably because they discarded the verbal description of the numerical information and focused solely on information in the icon arrays.

Figure 3(a) Percentage of participants whose estimates of risk reduction were accurate, lower, or higher than the exact value GSK-3 as a function of the sizes of the denominators and icon arrays when information about risk reduction was provided in English. (b) Percentage …4. The Impact of Graph Literacy on the Assessment of Treatment Risk Reduction As the studies reviewed above suggest, visual displays such as icon arrays can significantly improve understanding of ratio concepts. However, graphs are not equally useful for all individuals [26, 39, 57]. Recent research has shown that people differ substantially in their ability to understand graphically presented information, or graph literacy [32, 58]. Individuals with high graph literacy have been found to make more elaborate inferences when viewing graphical displays, as compared with less graph-literate individuals.