Public Use Microdata Sample (PUMS) files and the 2009 SNAP Quality Control file (SNAP QC). The data support an investigation of the potential undercount of SNAP participation in student households by the ACS at the national and state levels.

The SNAP QC data are sample-based administrative data that are representative at the state level and contain detailed demographic, economic, and SNAP eligibility information for an annual sample of more than 45,000 SNAP households. The data are weighted to match administrative counts of individuals and households receiving benefits and the amount of benefits received (adjusted to remove ineligible households that received benefits in error and those receiving disaster assistance benefits). The SNAP QC data represent all SNAP participants regardless of where they live (so noninstitutionalized group quarter residents are included).¹

The SNAP QC data do not include all individuals in households where someone receives SNAP benefits. The data include individuals in the SNAP filing unit (those covered by SNAP), and only those individuals outside the filing unit (but in the household) whose income or assets would be counted in determining eligibility and benefits. The tables below include individuals in the filing unit as well as any other individuals in the household that are included in the SNAP QC data. There are about 1.85 children per SNAP household in the SNAP QC data.

In the ACS, SNAP participation is a household question, but it is also asked of group quarter respondents. We counted a household as having SNAP benefits if the household question was answered in the affirmative. We counted everyone living in that household as receiving SNAP benefits. According to the ACS, there were 1.89 children in each SNAP household in 2009, compared with 1.85 children per SNAP household in the SNAP QC data. Differences in household sizes across the two data sets are discussed below. On the ACS, the group quarter respondents who reported SNAP participation were split approximately evenly between institutional and noninstitutional group quarters; only those in noninstitutional group quarters are included in the tables below.

There is an additional difference in the way eligibility is determined in the two data sets. In SNAP QC, eligibility is based on income and filing unit as reported on an application (and determined to be accurate). The SNAP QC file has monthly income,² and eligibility is based on a

¹ Related children are people who are aged 5-17 and related by birth, marriage, or adoption to the householder of the housing unit in which they reside; foster children, other unrelated individuals, and residents of group quarters are not considered related children.

² Estimates were also released in 1995 and 1997.