Abstract Although there are numerous longitudinal studies of happiness, the majority focus on its predictors, with few considering happiness itself as a predictor, while those that do focus only on select outcomes. Our paper offers a more expansive perspective by analysing the Global Flourishing Study (GFS), a panel study investigating myriad predictors and outcomes of flourishing in 22 diverse countries. We explore the impact of happiness at wave 1 (207,919 participants) on 56 flourishing-related outcomes at wave 2 (124,776, a retention rate of 62%). For each outcome we conducted a multivariate regression analysis within each country (with random-effects meta-analyses used to pool estimates across countries), regressing each Wave 2 outcome on Wave 1 happiness, using two models: model 1 is less conservative, controlling only for demographic and childhood variables, whereas model 2 controls for seven principal components extracted from all contemporaneous Wave 1 variables. Even in the latter, which risks over-control, happiness had a robust association with most aspects of flourishing, including an effect size of 0.16 with a six-domain flourishing index, which was highest among all 68 Wave 1 exposures (alongside life satisfaction and meaningful activities). Besides its longitudinal nature, another strength of the GFS is its multi-national design, which revealed considerable variation in effect sizes, which for the flourishing index ranged from Hong Kong (0.30), Australia (0.26), and the US (0.26) at the top, to China, Kenya, Tanzania (0.04) and Egypt (0.03) at the low end. While there may be some evidence that happiness is causally important for flourishing, such effects thus seem unevenly distributed, both across outcomes and countries, though more research is required to delve into why such variation is observed.
Lomas et al. (Mon,) studied this question.