As noted in the report, two samples of families from the Fragile Families dataset were selected for re-analysis. An initial sample was limited to families where the mother is 18 years of age or older and has a household income at their Year 1 interview at or below the national poverty threshold based on the year of their interview (1999 through 2001). The second sample, the primary sample used for these analyses, is limited to families where the household income at Year 1 was at or below 50 percent of the national poverty rate.
The one-year followup was used as the time period to measure household income, instead of the baseline, because residential information was not collected until the Year 1 followup, so it matches the time point that homelessness could first be measured. Analyses also showed that approximately one-fifth of the households classified as being below the poverty line at baseline were above the poverty line at Year 1, indicating that the use of baseline income data might too widely broaden the pool of households in the analyses.
A question concerning household income included in the Year 1 Fragile Families survey was the first source of income data used. Of the 4,365 households in the Year 1 sample, 2,525 (58%) gave their total household income. For those women who could not give an exact dollar amount, a followup question asked them for at least an income range. An additional 1,426 woman (33%) answered this question. Using the midpoint of the range as an estimate, household income data was thus available on 91 percent of the Year 1 sample.
The household income information, together with information on household composition (number of children and other adults) was used to determine whether a household was above or below the poverty line. In 1999, for example, a household with one adult and one child needed to have a household income below $11,483 to meet the poverty threshold, while a family with two adults and two children had to be below $16,895. For those families missing any household income information, questions about the receipt of welfare/TANF or Food Stamps were used to indicate whether the family met the poverty criterion. Using these various measures, a total of 1,756 (36%) families were considered part of the poverty sample.
To determine whether families were at or below 50 percent of the poverty threshold, each income criteria (specified by household size) was divided in half. Since no other proxy measure, such as receiving TANF of Food Stamps, appeared to be a reliable indicator of being 50 percent below the poverty level, households with missing income data were excluded from this sample. A total of 838 families (17% of the entire Fragile Families dataset; 48% of the poverty sample) meet these more stringent income qualifications.