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

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.