3.4. Measures
3.4.1. Dependent variable: healthy behaviors
The dependent variable is a time-varying index of healthy behaviors similar to the index created by Breslow and colleagues through the Alameda County Survey (e.g. Belloc & Breslow 1972; Breslow & Enstrom, 1980; Wiley & Camacho 1980). This index predicts incidence of chronic disease, disability, and mortality in populations of adults over and above predictions provided by individual health behaviors. Add Health respondents self-report healthy behaviors at each wave and I include all three waves of healthy behaviors in the analyses that follow. I assign each of six healthy behaviors a value of 1 or 0, where 1 signifies that the individual engages in the behavior and 0 signifies that the individual does not report the behavior. An index of the six healthy behaviors is constructed by summing the scores for individual healthy behaviors, resulting in a score of 0–6 for each individual at each interview.2
Each variable is described in detail below: