Abstract We test for an effect of Arizona's 2007 Legal Arizona Workers Act (LAWA) on the proportion of the state's population characterized as noncitizen Hispanic. We use the synthetic control method to select a group of states against which Arizona's population trends can be compared. We document a notable and statistically significant reduction in the proportion of the Hispanic noncitizen population in Arizona. The decline observed matches the timing of LAWA's implementation, deviates from the time series for the synthetic control group, and stands out relative to the distribution of placebo estimates for other states in the nation.

Changes in the treatment of individuals by the criminal justice system following a policy intervention may bias estimates of the effects of the intervention on underlying criminal activity. We explore the importance of such changes in the context of the Immigration Reform and Control Act of 1986 (IRCA). Using administrative data from San Antonio, Texas, we examine variation across neighborhoods and ethnicities in police arrests and in the rate at which those arrests are prosecuted. We find that changes in police behavior around IRCA confound estimates of the effects of the policy and its restrictions on employment on criminal activity.