Our study used data from SIPP to examine the income and employment experiences of single mothers who exited poverty during the 2001 to 2003 period. In particular, we identified a sample of 615 single mothers who exited poverty during 2001 and tracked their experiences over the subsequent two-year period. In this section, we briefly describe our approach to conducting the various analyses described above. A detailed discussion of our methodological approach is provided in the Appendix.
Descriptive Analyses. Our study is primarily based on descriptive analyses in which we tabulated means and distributions of variables of interest. All figures were calculated using longitudinal sample weights in SIPP to make the findings representative of the U.S. civilian population in April 2001. Descriptive methods were used in analyses to (1) calculate poverty rates and poverty exit rates among single mothers in 2001; (2) profile single mothers who exited poverty in 2001 and how they compared to other single mothers; (3) profile the three groups of single mothers who exited poverty based on their poverty and non-poverty spells during the two-year follow-up period; and (4) compare the income, poverty, and job experiences of the three groups over the follow-up period. Where relevant, we conducted t-tests or chi-square tests to gauge whether or not observed differences in variable distributions across different groups of single mothers are statistically significant.(4)
We also used descriptive methods to identify key events that might have triggered sample members' initial poverty exits and their subsequent poverty reentries. In our analysis, we identified trigger events over a two-month window and a four-month window prior to the poverty exit and examined the proportion of sample members who exited poverty via various pathways.
Finally, we used life-table methods to look at the duration of non-poverty spells as well as subsequent poverty spells. These methods account for right-censored spells — that is, spells that were ongoing at the end of the follow-up period.
Multivariate Analyses. We conducted multivariate analyses to examine the relative importance of individual and job characteristics associated with successful poverty exits. In these analyses, we also included as model covariates national- and state-level data on economic conditions, poverty levels, and welfare rules. We estimated logit models where we modeled, as a function of covariates, the probability that a sample member spent a significant fraction of the two-year follow-up period out of poverty. We also estimated multinomial logit models to examine factors associated with membership in each of the three groups of poverty exiters: (1) single mothers who exited poverty and stayed out of poverty, (2) those who returned to poverty and remained poor, and (3) those who cycled in and out of poverty.