Age and Life Satisfaction: Getting Control Variables under Control

Researchers investigating the relationship between age and life satisfaction have produced conflicting answers, via disputes over whether to include individual-level control variables in regression models. Most scholars believe there is a ‘U-shaped’ relationship, with life satisfaction falling towards middle age and subsequently rising. This position emerges mainly in research that uses control variables (for example, for income and marital status). This approach is incorrect. Regression models should control only ‘confounding’ variables; that is, variables that are causally prior to the dependent variable and the core independent variable of interest. Other individual-level variables cannot determine one’s age; they are not confounders and should not be controlled. This article applies these points to data from the World Values Survey. A key finding is that there is at best a negligible post-middle-age rise in life satisfaction – and the important implication is that there cannot then be a U-shaped relationship between age and life satisfaction.