The study appears to factor in short-term vs long-term happiness. Specifically, they ask respondents to project forward 5 years into the future: >For its Life

The study appears to factor in short-term vs long-term happiness. Specifically, they ask respondents to project forward 5 years into the future: >For its Life Evaluation Index, Gallup classifies Americans as "thriving," "struggling" or "suffering" according to how they rate their current and future lives