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 e.g. income and marital status. This approach is incorrect: regression models should control only ‘confounding’ variables, i.e., 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.