AEIA's report shows a half-century decline in marriage rates that ended 30 years ago for disadvantaged kids. The study found that the rise in single-parent families was due to the increase in the middle class, which led to a decrease in marriage rates. The analysis also showed that single-parent families had lower socioeconomic status and higher rates of poverty. The report concludes that social and economic factors play a significant role in the decline of marriage rates and the rise of single-parent families.