Effectiveness of personalized and interactive health risk calculators: a randomized trial

Risk calculators are popular websites that provide individualized disease risk assessments to the public. Little is known about their effect on risk perceptions and health behavior.

This study sought to test whether risk calculator features-namely, personalized estimates of one's disease risk and feedback about the effects of risk-mitigating behaviors-improve risk perceptions and motivate healthy behavior.

A web-based experimental study using simple randomization was conducted to compare the effects of 3 prediabetes risk communication websites. Setting The study was conducted in the context of ongoing health promotion activities sponsored by a university's human resources office. Patients Participants were adult university employees. Intervention The control website presented nonindividualized risk information. The personalized noninteractive website presented individualized risk calculations. The personalized interactive website presented individualized risk calculations and feedback about the effects of hypothetical risk-mitigating behaviors. Measurements Pre- and postintervention risk perceptions were measured in absolute and relative terms. Health behavior was measured by assessing participant interest in follow-up preventive health services.

On average, risk perceptions decreased by 2%. There was no general effect of personalization or interactivity in aligning subjective risk perceptions with objective risk calculations or in increasing healthy behaviors. However, participants who previously overestimated their risk reduced their perceptions by 16%. This was a significantly larger change than the 2% increase by participants who underestimated their risk. Limitations Results may not generalize to different populations, different diseases, or longer-term outcomes.

Compared to nonpersonalized information, individualized risk calculators had little positive effect on prediabetes risk perception accuracy or health behavior. Risk perception accuracy was improved in people who receive relatively "good news" about risk rather than "bad news."