TOKYO – October 31, 2026 -- Happiness shows the strongest parent-child link among three well-being measures in Japan, with a rank-rank slope of 0.25, according to Keio University researchers. Self-reported general health followed at 0.22, and mental health was weakest at 0.13. All three associations were statistically significant.
The study by Kayoko Ishii, Zhi-xiao Jia and Isamu Yamamoto appeared in the journal Review of Economics of the Household. It uses data from the Japan Household Panel Survey, run in association with Keio's Panel Data Research Center.
Panel data tracks two generations within the same families
The survey began in 2004 and has followed the same individuals for more than 20 years. It was later extended to participants' adult children, including those no longer living with their parents, so the team could link parent and child records.
Single survey responses can reflect temporary circumstances such as illness, employment or family changes. The researchers therefore combined observations from different years to estimate well-being over a lifetime. They then compared the relative positions of parents and children within their own generations.
Well-being persists less than household income across generations
Subjective well-being was generally less persistent between generations than household income in Japan. People's happiness and health may therefore be more independent of their parents' circumstances than their economic position is. The researchers stress that the figures do not mean parents determine a set percentage of their children's happiness.
Income, education, lifestyle and personality explained only part of the association. Agreeableness made a modest contribution to the happiness link, and much of the association remained unexplained. The relationship appeared somewhat stronger in wealthier households, but the difference was not statistically significant.
Compared with findings from other countries, Japan showed an intermediate degree of persistence in subjective well-being. Differences in healthcare, welfare systems and other institutions may contribute to cross-country variation, though the study does not establish causal effects.
Authors point to healthcare, psychological support and family welfare as policy levers
The findings indicate that efforts to reduce inequality may need to go beyond financial assistance and educational opportunity. Access to healthcare, psychological support and family welfare could also matter for equalizing opportunities for well-being.
Yamamoto said inequality in non-monetary areas such as health and well-being deserves attention alongside disparities in income and assets. Some differences emerge from competition, he said, but it is "more concerning" when starting points strongly affect later access to opportunity.
Two-year data window limits long-term estimates
The study identifies associations, not direct transmission of happiness or health from parents to children. Genetic influences, shared environments and economic circumstances may all contribute.
Data covered only two years for the children's generation, and for mental health in both generations. Estimates of longer-term well-being are therefore less certain than those based on more extensive observations. The authors call for further research using longer-term data and cross-country comparisons. The work received support from the Japan Society for the Promotion of Science under grant 22H04911.