CILS is a longitudinal study designed to study the adaptation process of the immigrant second generation which is defined broadly as U.S.-born children with at least one foreign-born parent or children born abroad but brought at an early age to the United States. The original survey was conducted with samples of second-generation children attending the 8th and 9th grades in public and private schools in the metropolitan areas of Miami/Ft. Lauderdale in Florida and San Diego, California.
The first survey, conducted in 1992, had the purpose of ascertaining baseline information on immigrant families; children’s own demographic characteristics; language use; self-identities; and academic attainment. The total sample size was 5,262. Respondents came from 77 different nationalities, although the sample reflects the most sizable immigrant nationalities in each area. Thus, the largest concentrations include Cubans, Haitians, Nicaraguans, and West Indians in South Florida; and Mexicans, Filipinos, Vietnamese, Laotians, and Cambodians in California. The sample is evenly divided by sex, year in school (8th, 9th) and birth status (foreign-born/U.S.-born). Fifty-four percent of the interviews were conducted in Miami/Ft. Lauderdale and 46 percent in San Diego.
Three years later, corresponding to the time in which respondents were about to graduate from high school, the first follow-up survey was conducted. Its purpose was to examine the evolution of key adaptation outcomes, including language knowledge and preferences; ethnic identity; self-esteem; and academic attainment over the adolescent years. The survey also sought to establish the proportion of second-generation youths who dropped out of school before graduation. This follow-up survey retrieved 4,288 respondents or 81.5 percent of the original sample. A series of statistical tests indicated that this follow-up is not seriously biased with respect to the original survey, although there is some overrepresentation of children from higher-status families.
Together with this follow-up survey, a parental survey was conducted. For reasons of cost, this survey targeted half of the total universe of parents, selecting them on a random basis. Unlike the student surveys, which were conducted mostly via self-administered questionnaires in school, the parental interviews were conducted face-to-face and mostly at home. Since many immigrant parents did not understand English, the questionnaire was translated and administered in six different foreign languages. The purpose of this interview was to establish directly characteristics of immigrant parents and families and their outlooks for the future, including aspirations and plans for the children. In total, 2,442 parents or 46 percent of the original student sample were interviewed. Their national origins closely resemble, in proportional terms, those of the student sample.
The third survey was conducted when respondents had reached early adulthood, at average age 24. This survey was conducted using a combination of mailed questionnaires, telephone, and in-person interviews. By then, most respondents had left their parents' home, requiring a nationwide tracking effort. In total, this follow-up survey retrieved 3,613 respondents representing 69 percent of the original sample and 84 percent of the first follow-up. There is evidence of sampling bias in the second follow-up requiring statistical corrections. This is explained in detail in Portes and Rumbaut (2005).
All CILS surveys were jointly directed by Alejandro Portes, initially at Johns Hopkins and now at Princeton University, and by Rubén G. Rumbaut, initially at San Diego State University and subsequently at Michigan State University and the University of California - Irvine.