We study costless pre-play communication of intentions among inexperienced players. Using the level-k model of strategic thinking to describe players' beliefs, we fully characterize the effects of preplay communication in symmetric 2×2 games. One-way communication weakly increases coordination on Nash equilibrium outcomes, although average payoffs sometimes decrease. Two-way communication further improves payoffs in some games but is detrimental in others. Moving beyond the class of symmetric 2 × 2 games, we find that communication facilitates coordination in common interest games with positive spillovers and strategic complementarities, but there are also games in which any type of communication hampers coordination.

We surveyed a large sample of Swedish lottery players about their psychological well-being 5–22 years after a major lottery event and analysed the data following pre-registered procedures. Relative to matched controls, large-prize winners experience sustained increases in overall life satisfaction that persist for over a decade and show no evidence of dissipating over time. The estimated treatment effects on happiness and mental health are significantly smaller. Follow-up analyses of domain-specific aspects of life satisfaction implicate financial life satisfaction as an important mediator for the long-run increase in overall life satisfaction.

We exploit the randomized assignment of lottery prizes in a large administrative Swedish data set to estimate the causal effect of wealth on stock market participation. A $150,000 windfall gain increases the stock market participation probability by 12 percentage points among prelottery nonparticipants but has no discernible effect on prelottery stock owners. A structural life cycle model significantly overpredicts entry rates even for very high entry costs (up to $31,000). Additional analyses implicate pessimistic beliefs regarding equity returns as a major source of this overprediction and suggest that both recent and early-life return realizations affect beliefs.

We use administrative data on Swedish lottery players to estimate the causal impact of substantial wealth shocks on players’ own health and their children’s health and developmental outcomes. Our estimation sample is large, virtually free of attrition, and allows us to control for the factors conditional on which the prizes were randomly assigned. In adults, we find no evidence that wealth impacts mortality or health care utilization, with the possible exception of a small reduction in the consumption of mental health drugs. Our estimates allow us to rule out effects on 10-year mortality one sixth as large as the cross-sectional wealth-mortality gradient. In our intergenerational analyses, we find that wealth increases children’s health care utilization in the years following the lottery and may also reduce obesity risk. The effects on most other child outcomes, including drug consumption, scholastic performance, and skills, can usually be bounded to a tight interval around zero. Overall, our findings suggest that in affluent countries with extensive social safety nets, causal effects of wealth are not a major source of the wealth-mortality gradients, nor of the observed relationships between child developmental outcomes and household income.

We study the effect of wealth on labor supply using the randomized assignment of monetary prizes in a large sample of Swedish lottery players. Winning a lottery prize modestly reduces earnings, with the reduction being immediate, persistent, and quite similar by age, education, and sex. A calibrated dynamic model implies lifetime marginal propensities to earn out of unearned income from −0.17 at age 20 to −0.04 at age 60, and labor supply elasticities in the lower range of previously reported estimates. The earnings response is stronger for winners than their spouses, which is inconsistent with unitary household labor supply models.