Abstract This study examined whether and how survey response differs by race and Hispanic origin, using data from birth certificates and survey administrative data for a large-scale statewide experiment. The sample consisted of mothers of infants selected from Oklahoma birth certificates using a stratified random sampling method (N= 7,111). This study uses Heckman probit analysis to consider two stages of survey response: (1) being located by the survey team and (2) completing a questionnaire through collaboration with the survey team. Analysis results show that African Americans, American Indians, and Hispanics are significantly less likely to be located during the study recruitment than white Americans, controlling for other demographic and socioeconomic factors. Conditional on being located, the probability of collaboration did not differ among the four groups. Findings suggest that researchers should pay attention to separate stages of respondent recruitment and improve strategies to locate members of racial and ethnic minority groups during recruitment. KEY WORDS: Hispanic origin; noncontact; nonresponse; race; survey research Racial and ethnic inequality in socioeconomic status (SES) and health is a serious concern among social work practitioners and researchers. White Americans have, on average, advantaged positions over minority groups in educational achievement, employment status, income, wealth, and health (Bauman & Graf, 2003; Shapiro, 2004). For example, college-educated individuals represent 55% of non-Hispanic white Americans, but only 43% of African Americans, 42% of American Indians, and 30% of Hispanics (Bauman & Graft 2003). In terms of wellness indicators, racial and ethnic minority groups art- estimated to have poorer health than white people and to have more limited access to needed medical and preventive health care (Liao et al., 2004). Despite huge gaps in socioeconomic achievement, health, and other well-being measures, understanding of the causes of and solutions to these disparities is limited (Yancey, Ortega, & Kumanyika, 2006). One barrier to understanding racial and ethnic disparities is a lack of representative data for each racial and ethnic group. Accordingly, a methodological focus for many decades among social scientists, especially survey researchers, has been how to generate representative data from all racial and ethnic groups (Hirschman, Alba, & Farley, 2000; Johnson, O'Rourke, Burris, & Owens, 2002; Yancey et al., 2006). Knowledge and experience in achieving representative samples, recruiting survey respondents, and collecting accurate information from study target populations have recently expanded (Baines, Partin, Davern, & Rockwood, 2007; Groves, 2006), but strategies and tactics are still far from perfect (Yancey et al., 2006). One potential obstacle to collecting reliable and valid data is unequal survey response rates among racial and ethnic groups. If response rates are consistently low among certain racial and ethnic groups, it may be hard to generate data representative of these groups (Yancey et al., 2006). Little is known, however, about how and why survey response varies among racial and ethnic groups. To shed new light on survey response by race and ethnicity, this study took advantage of data from a statewide social experiment, SEED for Oklahoma Kids (SEED OK hereinafter). This study is unique in that the sample was drown from a sampling flame with information on demographic and social status--2007 birth certificate data provided by the Oklahoma State Department of Health (OSDH). Data from the sampling frame enabled us to compare characteristics between respondents and nonrespondents. Moreover, we separated the survey response process into two stages: (1) being located by the survey team (location), and (2) completing the questionnaire through collaboration with the survey team (collaboration). In this way, we investigated differences among white Americans, African Americans, American Indians, and Hispanics at two distinct stages of overall survey response: location and collaboration. …