Absence of conflict of interest.
The study’s objective was to examine the impact of immigration policies after September 11, 2001, on self-employment among Mexican immigrants.
The study used a difference-in-differences model using Current Population Survey (CPS) data from 1996 to 2006.
The study found Mexican immigrants were substantially more likely to enter self-employment after 9/11, but there was no statistically significant difference in overall rates of self-employment.
The quality of causal evidence presented in this report is low because the events of 9/11 present a confounding factor. This means we are not confident that the estimated effects are attributable to immigration policies after 9/11; other factors are likely to have contributed.
Post-9/11 Immigration Policies
Features of the Intervention
After 9/11, immigration policies in the United States became stricter and their enforcement increased. Because enforcement actions, such as raids, typically take place at work sites, the increase in such actions could result in immigrant populations pursuing self-employment as an alternative to seeking other employment opportunities.
The study examined the impact of the post-9/11 immigration policies on male, non-citizen Mexican immigrants.
Features of the Study
The author compared changes in self-employment of male and non-citizen Mexican immigrants to less-educated White men from 1996 to 2006 using a difference-in-difference analysis. The 11-year period included five years before and five years after 2001. The sample included men in their prime working ages (ages 18 to 55) and not in the armed forces or living in group quarters. The intervention group, non-citizen male Mexican immigrants, was subject to the intervention. The control group comprised less-educated non-Hispanic native-born White malesmen, who would not have been subject to the intervention. The author used monthly data from the CPS to assess outcomes. The CPS, a large, nationally representative data set, contains information on the employment status of the same person in at least two periods. The author used a statistical model to compare the outcomes of intervention and comparison group members.
The study found that after 9/11, male Mexican immigrants entered self-employment at a rate 0.2 percentage points higher than less-educated White men (the difference is statistically significant). The study did not find a significant relationship between post-9/11 immigration policies and the self-employment rate or the exit rate from self-employment.
Considerations for Interpreting the Findings
The author accounted for demographic variables including sex, age, and race.
The author used falsification tests to assess for any differences in pre-existing trends in employment for the intervention and comparison groups. All effects were not statistically significant, indicating a lack of pre-existing trends.
Causal Evidence Rating
The quality of causal evidence presented in this report is low because the events of 9/11 present a confounding factor. Aside from immigration policies, 9/11 might have affected male Mexican non-citizen immigrants and less-educated White men differently. Therefore, we are not confident that the estimated effects are attributable to the post-9/11 immigration policies; other factors are likely to have contributed.