In pursuit of happiness: Why income isn't the end of the story

This study re-examines the relationship between income and happiness by proposing an integrated framework that captures both the nonlinear and reciprocal nature of the income–well-being nexus. While conventional analyses focus predominantly on the one-directional effect of income on subjective well-being, we argue that happiness itself is an important economic input that shapes productivity and, ultimately, GDP per capita. Using panel data for 15 European countries from 1995 to 2020, we combine X-means clustering with simultaneous-equations panel modelling to test these dynamics. The results provide robust empirical support for an inverted U-shaped relationship between income and happiness: life satisfaction rises with GDP per capita up to a threshold and then declines at very high-income levels. Moreover, we find strong evidence of two-way causality, with happiness exerting both immediate and lagged positive effects on total factor productivity and GDP per capita. These findings challenge the traditional income-centered view of welfare, demonstrating that material prosperity alone is insufficient for sustained improvements in life satisfaction once basic needs are met. The analysis emphasizes the importance of complementary factors—such as education, environmental quality, and work–life balance—in shaping well-being and offers critical insights for the design of policies aimed at enhancing societal welfare in advanced economies. • Income and happiness have a strong two-way causal relationship. • Happiness boosts productivity and future income growth. • The income-happiness link is an inverted U-shape, not linear. • Beyond a point, higher income does not increase happiness. • Education, environment, and work hours critically impact well-being.