Aiding risk information learning through simulated experience (ARISE): Using simulated outcomes to improve understanding of conditional probabilities in prenatal Down syndrome screening

Abstract

Objective: To determine whether the use of simulated experiences to communicate statistical information can improve an individual's understanding of conditional probabilities-specifically the positive predictive value (PPV) of prenatal screening tests for Down syndrome.

Methods: In Experiment 1 (N=64) and Experiment 2 (N=180) participants were asked to estimate the PPV of a prenatal screening test for Down syndrome based on either (1) explicit statistics regarding the prevalence of Down syndrome and the sensitivity and specificity of a prenatal screening test for Down syndrome, or (2) experiencing up to 5000 simulated test results over a short time.

Results: Participants' estimates of the PPV were more accurate when they had learned via simulated experiences (79% accuracy) compared with estimates based on explicitly described statistics (14%). Participants in the simulated experience condition also reported decreased interest in screening and decreased concern with a positive test result.

Conclusion: Simulated experiences improve PPV estimates, compared to estimates derived from explicitly provided statistics, while also shifting attitudes away from screening.

Practice implications: The use of simulated experiences may prove to be simple but powerful tool to communicate complex statistical information to patients in medical decision making situations.

Keywords: Attitudes towards screening; Conditional probabilities; Positive predictive value; Screening tests; Simulated experience.