@TechReport{iza:izadps:dp7942,
            	author={Cheng, Terence Chai and Powdthavee, Nattavudh and Oswald, Andrew J.},
            	title={Longitudinal Evidence for a Midlife Nadir in Human Well-being: Results from Four Data Sets},
            	year={2014},
	month={Feb},
            	institution={Institute of Labor Economics (IZA)},
            	address={Bonn},
            	type={IZA Discussion Paper},
            	number={7942},
            	url={https://www.iza.org/index.php/publications/dp7942},
	abstract={There is a large amount of cross-sectional evidence for a midlife low in the life cycle of human happiness and well-being (a 'U shape'). Yet no genuinely longitudinal inquiry has uncovered evidence for a U-shaped pattern. Thus some researchers believe the U is a statistical artefact. We re-examine this fundamental cross-disciplinary question. We suggest a new test. Drawing on four data sets, and only within-person changes in well-being, we document powerful support for a U-shape in unadjusted longitudinal data without the need for regression equations. The paper's methodological contribution is to exploit the first-derivative properties of a well-being equation.},
	keywords={longitudinal study;subjective well-being;life-cycle happiness;U shape},
            }