ON THE EFFECTIVENESS OF SB1070 IN ARIZONA

I. INTRODUCTION During the past years, as the national immigration debate stalled, states started to take immigration enforcement into their own hands. Recent proposals at the state and local government level included the passage of laws where local authorities may ask a person suspected of being in the United States illegally to show proof of documented legal status in the country. Among these proposals perhaps the most controversial one has been Arizona's Senate Bill 1070 (SB 1070), which was passed into law in April 2010 and enforced in July 2010 (later it was changed to AZ House Bill 2162). The Act forbids state and local officials from avoiding or limiting the enforcement of federal immigration laws. It also persecutes the transporting, sheltering, or hiring of illegal aliens. But what has attracted the most attention in the press and political debates, especially after being recently upheld by the Supreme Court, has been the so-called "show me your papers" clause. The clause calls for police to make an effort to determine the immigration status of any person suspected of being an illegal alien during a lawful stop. Lack of proper documentation in the form of any valid federal, state, or local government-issued identification by an alien is considered a misdemeanor and can carry a fine of up to $100, court costs, and up to 20 days in jail for a first offense. (1) Although the effectiveness of this bill may be limited with its most controversial parts blocked by the Courts, (2) there are reasons to believe that SB 1070 may have had a significant chilling effect and successfully achieved its aim of reducing the incidence of unauthorized immigration in the state. In this article, we examine whether that has been the case. Recent work by Lofstrom, Bohn, and Raphael (2014) has shown how the employment verification mandate to all employers contained in the 2007 Legal Arizona Workers Act (LAWA)--henceforth universal E-Verify (3)--reduced the shares of non-citizen Hispanics, a group more likely to encompass "likely unauthorized immigrants." Hence, a priori, one might expect SB1070 to be particularly effective in further reducing the share of likely unauthorized immigrants in the state. After all, omnibus immigration laws (OILs) are significantly tougher in at least two regards. First, unlike E-Verify mandates, OILs target all likely unauthorized immigrants, not just those formally applying for a job. Anybody can be stopped and asked for proper documentation. Secondly, unlike E-Verify mandates, OILs are directly linked to police enforcement and deportation, thus imposing a much greater risk to likely unauthorized immigrants than the risk of being found ineligible for employment through an employment verification system. Nevertheless, the effectiveness of SB1070 depends, to some degree, on that of its predecessor. If LAWA was particularly effective at reducing the share of likely unauthorized immigrants in the state, it is possible that SB1070 might not have added much. Thus, our questions are the following: Has SB1070 proven effective in further reducing the share of likely unauthorized immigrants in the state? And, if so, how? Has it complemented the E-Verify mandate in LAWA by targeting specific subgroups within the likely unauthorized population less impacted by its predecessor? To answer these questions, we assess the impact of SB1070, as well as how it may have differed from that of the E-Verify mandate in LAWA. We do so by, first, estimating the joint impact of LAWA and SB1070 in deterring potentially undocumented immigrants from settling in Arizona. We then compare the estimated joint impact of LAWA and SB1070 to the effect of LAWA up until the enactment of SB1070. For the analysis, we extract monthly data from the Current Population Surveys (CPSs) for the period running from January 1998 through December 2013--a period long enough to gauge the effectiveness of both LAWA and SB1070. Using those data, we implement the quasi-experimental approach proposed by Abadie, Diamond, and Hainmueller (2010) to learn about the effectiveness of SB1070 in reducing the shares of "likely unauthorized immigrants" in Arizona relative to states in a synthetic control group. …