Estimating Visa Overstays: The 3-Card Method

• Activity Number: 148
• Type: Contributed
• Date/Time: Monday, August 12, 2002 : 2:00 PM to 3:50 PM
• Sponsor: Social Statistics Section*
• Author(s): Judith Droitcour*+ and Nathan Anderson
• Affiliation(s): U.S. General Accounting Office and U.S. General Accounting Office
• Keywords: overstays ; randomized-response ; indirect ; 3-card ; immigration

Abstract

Visa overstays represent a category of illegal immigrantion that is of heightened concern, given the events of 9/11. The three-card method is a survey-based indirect estimation technique that assures absolute privacy of response. No one--whether interviewer, data analyst, principal investigator, or anyone else--can ever know whether a respondent is in the sensitive category, based on his or her responses. Yet when all data are combined, an estimate of the sensitive category is possible. The method was initially designed to: 1.) avoid the "mind-boggling" procedures in a randomized response interview; 2.) allow follow-up questions; and 3.) estimate all major immigration catgories, including the sensitive illegal-immigrant category, for the total population and subgroups. The initial version could not "break-out" visa overstays, but a new version allows such an estimate. This paper concerns the variance associated with a three-card estimate of visa overstays (for the total foreign-born population and for key subgroups, e.g., region of origin). Findings are presented from a simulation and from analyses exploring the use of analytic methods (e.g., multiple imputation) for variance reduction.