State Law and Illegal Immigrants: A Study of Confounding of the Effects ofArizona SB 1070 Policy

Illegal immigration has long been a controversial issue in the U.S. In this paper, wewill discuss the robustness of the findings in Illegal Immigration, State Law, andDeterrence (Hoekstra and Orozco-Aleman, 2017), in which the authors examine theeffectiveness of Arizona SB 1070, allegedly one of the strictest immigration law everpassed to address the issue. Hoekstra and Orozco-Aleman (will be referred to as H& O-A going forward) show that the passage of the legislation reduced the flowof illegal border crossings into Arizona up to 70% which leads to the conclusionthat potential undocumented immigrants are responsive to Arizona SB 1070. Usingthe approach for sensitivity analysis introduced in Cinelli and Hazlett (2020), wefind that the robustness of the authors’ findings are mixed among their study de-signs. However, all designs yield the same results, and an additional model usingBaysesian approach also supports such results. This suggests that even though thefindings may be indeed valid, they may be vulnerable to certain observable or un-observable confounders, and these concerns should be addressed in future studies