Closing the gap: How wearable data reduces mortality slippage in accelerated underwriting

Two of the largest sources of mortality slippage in accelerated underwriting are missing fluid information and smoker misrepresentation. In collaboration with Klarity^[1], WTW tested whether using the Klarity predictive model’s wearable-based risk score — analyzed in our July 2025 paper, “Reclassifying Mortality Risk” — can narrow that gap without the protective value of fluids.

Background: Reclassifying mortality risk with wearable-based data

WTW’s July 2025 paper centered on our analysis of Klarity’s mortality risk predictive model and the powerful predictive value of leveraging activity- and inactivity-based data in the risk selection process. The Klarity model classifies individual risk using a Z-score, which reflects how much a person’s predicted risk deviates from the average for their age and gender group.

From fluids to no fluids: Adapting the model for AUW

Our initial study focused on the additive value of activity-based data and the model risk score to underwriting, where certain fluid variables, such as cholesterol, were also included in the model scoring.

Given the prevalence of more accelerated underwriting (AUW) programs in the U.S., where fluid variables from insurance labs and physical measurements are often waived, we reviewed if the model risk score when no fluids were included could be leveraged to reduce the mortality slippage that results from missing fluid information and smoker misrepresentation, which continues to be a challenge for most AUW programs.

Findings: The additive value of the Klarity risk score

WTW found inclusion of alternative activity-based data, is additive to the risk selection process. In this study, we found adding the Klarity model’s risk score, even when fluid or insurance lab data are included, improves the ability to better segment the risks within a targeted risk class. Thus, we believe the inclusion of the Klarity risk score can likely reduce the mortality slippage observed in AUW due to certain misrepresentation.

Footnote

1. Klarity is a U.K.-based predictive analytics company that provides preventive health solutions. Its proprietary mortality and morbidity risk prediction models leverage advanced data sources such as wearables, electronic health records and blood biomarkers. Return to article undo