Is More Always Better? The Relation Between Socioeconomic Status and Human Development

Socioeconomic status (SES) is one of the most well researched constructs in developmental science, yet important questions underly how to best model it. That is, are relations with SES always in the same direction or does the direction of association change at different levels of SES? In this dissertation, I conducted a meta-analysis using individual participant data (IPD) to examine two questions: 1) Does a nonmonotonic (quadratic) model of the relations between components of SES (i.e., income, years of education, occupation status/prestige), depressive symptoms, and academic achievement fit better than a monotonic (linear) model? and 2) Is the magnitude of relation moderated by developmental period, gender/sex, or race/ethnicity? I hypothesized that there would be more support for the nonmonotonic model. Moderation analyses were exploratory.
I identified nationally representative IPD from the Inter-university Consortium for Political and Social Research (ICPSR). I included 59 datasets, which represent 23 studies (e.g., Add Health) and 1,844,577 participants. Higher income (β = -0.11; β = 0.10), years of education (β = -0.09; β = 0.13), and occupational status (β = -0.04; β = 0.04) and prestige (β = -0.03; β = 0.04) were associated with a linear decrease in depressive symptoms and increase in academic achievement, respectively. Higher income (β = 0.05), years of education (β = 0.02), and occupational status/prestige (β = 0.02) were quadratically associated with a decrease in depressive symptoms followed by a slight increase at higher levels of income and a diminishing association towards higher levels of education and occupational status/prestige. Higher income was also quadratically associated with academic achievement (β = -0.03). I found evidence that these associations varied between developmental periods and racial/ethnic samples, but I did not find evidence of variation between females and males.
I integrate these findings with three conclusions: (1) more is not always better and (2) there are unique contexts and resources associated with different levels of SES that (3) operate in a dynamic fashion with other cultural systems (e.g., racism), which affect the integrated actions between the individual and context. I outline several measurement implications and limitations for future research directions.