Abstract

Objectives

To estimate monetary values of health and health behavior outcomes and 1 well-being-adjusted life-year (WELLBY) in Japan using the well-being valuation approach for cross-sector policy evaluation and social return on investment analysis.

Methods

We analyzed data from a nationwide Internet-based survey conducted between February and March 2025, including 14 736 adults aged 20 to 79 years. One WELLBY was defined as a 1-point change in life satisfaction on a 0 to 10 scale sustained for 1 year. Using life satisfaction as the primary well-being measure, we estimated the income-subjective well-being gradient using 2-stage least squares with parental education as an instrumental variable. We examined associations between subjective well-being and 19 outcomes across mental health, social health, health behaviors, health literacy, and women’s health. We calculated compensating surplus values in Japanese yen anchored to the median equivalized household income.

Results

The instrumental variables were strong, and the coefficient of log income on life satisfaction was 2.27. Of the 19 outcomes examined, 18 were significantly associated with subjective well-being (P cognitive restraint (TFEQ-CR) was the sole nonsignificant outcome. Monetary values per 1-point increase included ¥120 000 for the Lubben Social Network Scale-6 and −¥226 000 for the Patient Health Questionnaire-9. A 1-point increase in loneliness corresponded to a welfare loss of −¥513 000. The estimated value of 1 WELLBY was approximately ¥1.51 million (∼US$10 000).

Conclusions

This study provides Japan’s first yen-denominated set of monetary values for health-related outcomes and WELLBY, enabling cost-benefit analysis and social return on investment across sectors.