LANYCIS had a complex, stratified sample. Because of the interest in food stamp recipients and low-income families, we oversampled households that met those criteria. In general, our goal was to obtain roughly equal sample sizes in both cities. In each city, it was hoped that about half the unweighted sample of households had received food stamps in 1996 or 1997, about one-quarter had incomes below 200 percent of the poverty level but did not get food stamps in 1996 or 1997, and one-quarter had incomes over 200 percent of the poverty level.
The survey used an amalgam of three sampling approaches.
1. The main sampling approach was a random digit dial (RDD) telephone survey of residences in Los Angeles County and New York City.
2. The second method used a list sample of addresses of food stamp recipient households, based on administrative data of 1997 participants provided by the local welfare agencies. Where possible, the appropriate households were telephoned. When there was no telephone number (or where the listed phone number did not work), interviewers were sent to the listed address for an in-person interview (or to get a phone number for a telephone interview). In this component of the sample, we did not require that the household interviewed be the same one listed on the administrative list, but any eligible household at that address. That is, the administrative lists can be viewed as a list of addresses with a high probability of being immigrant food stamp households.
3. There was originally a small area sample for in-person interviews of households without telephones. This yielded very few respondent households, however, so we terminated this approach early. To help represent non-telephone households, we used a Keeter adjustment that adjusts weights on the assumption that people with periodic phone service interruptions are similar to non-telephone households (Keeter 1995; Brick et al. 1999).
All interviews were conducted by computer-assisted methods, using either computer-assisted telephone interviews (CATI) fielded from UCLA's telephone facility or using computer-assisted personal interviews (CAPI) by professional interviewers based in Los Angeles or New York City using laptop computers. Most interviews were conducted by telephone, but some were done with in-person interviews, particularly those drawn from the food stamp administrative lists.
All households were informed of the purpose of the interview and of their right to refuse to participate or to not answer any question and they were promised confidentiality, following procedures approved by the Urban Institute's Institutional Review Board. A limited number of respondents, particularly those contacted in person, were offered incentive payments of $10 to participate in the study.