Medicaid use by documented and undocumented farm workers.

Background: Despite considerable debate surrounding the use of Medicaid by undocumented immigrants, few studies address the extent of this use or estimate differences in the use between documented and undocumented households.

Method: We analyzed data from the National Agricultural Workers Survey annual cross sections from 1993 through 2009, N = 41,342. Simple mean differences and logistic regressions predicted participation in Medicaid over 2-year intervals.

Results: Without adjustments for covariates, 12.2% of undocumented farm workers' households and 22.6% of documented households received Medicaid benefits, corresponding to an odds ratio of 0.48 (95% confidence interval, 0.33 to 0.69). By adding only covariates reflecting presence of children in the household, the odds ratio increased to 0.86 (95% confidence interval, 0.73 to 1.02).

Conclusions: Undocumented farm workers' households were roughly half as likely to use Medicaid as documented households, and undocumented households' participation was especially responsive to the presence of children.