Visual aids improve diagnostic inferences and metacognitive judgment calibration

Abstract

Visual aids can improve comprehension of risks associated with medical treatments, screenings, and lifestyles. Do visual aids also help decision makers accurately assess their risk comprehension? That is, do visual aids help them become well calibrated? To address these questions, we investigated the benefits of visual aids displaying numerical information and measured accuracy of self-assessment of diagnostic inferences (i.e., metacognitive judgment calibration) controlling for individual differences in numeracy. Participants included 108 patients who made diagnostic inferences about three medical tests on the basis of information about the sensitivity and false-positive rate of the tests and disease prevalence. Half of the patients received the information in numbers without a visual aid, while the other half received numbers along with a grid representing the numerical information. In the numerical condition, many patients-especially those with low numeracy-misinterpreted the predictive value of the tests and profoundly overestimated the accuracy of their inferences. Metacognitive judgment calibration mediated the relationship between numeracy and accuracy of diagnostic inferences. In contrast, in the visual aid condition, patients at all levels of numeracy showed high-levels of inferential accuracy and metacognitive judgment calibration. Results indicate that accurate metacognitive assessment may explain the beneficial effects of visual aids and numeracy-a result that accords with theory suggesting that metacognition is an essential part of risk literacy. We conclude that well-designed risk communications can inform patients about healthrelevant numerical information while helping them assess the quality of their own risk comprehension.

Keywords: Bayesian reasoning; diagnostic inferences; medical decision making; natural frequencies; numeracy; risk literacy; visual aids.

FIGURE 1

Visual aid representing the overall number of women at risk, the number of women who have breast cancer, and the number of women who obtained a positive mammogram.

FIGURE 2

Estimated accuracy by objective accuracy. Error bars indicate one standard error of the mean.

FIGURE 3

Objective accuracy, estimated accuracy, and metacognitive judgment calibration across the three diagnostic tasks by information format and numeracy. Error bars indicate one standard error of the mean.

FIGURE 4

Objective accuracy across the three diagnostic tasks by information format and numeracy after controlling for the effect of metacognitive judgment calibration. Metacognitive judgment calibration across the three diagnostic tasks by information format and numeracy after controlling for the effect of objective accuracy. Error bars indicate one standard error of the mean.

FIGURE 5

Path analyses. Effect of numeracy on objective accuracy and the mediational effect of metacognitive judgment calibration when (A) patients received information only in numbers and when (B) they received an additional visual display representing the numerical information. Effect of numeracy on metacognitive judgment calibration and the mediational effect of objective accuracy when (C) patients received information only in numbers and when (D) they received an additional visual display representing the numerical information. Note: Standardized coefficients are shown. *p < 0.05.