ETHNIC ENCLAVES are communities with high concentrations of one ethnic group, usually resulting from immigration patterns. Many scholars believe that they slow immigrant assimilation into U.S. society, a phenomenon known as the "enclave thesis." Recent academic literature on the enclave thesis has yielded mixed results, but there also are severe research design problems due to data limitations, a lack of definitional consensus, and seemingly insurmountable endogeneity.
Concerns about ethnic enclaves, specifically their impact on assimilation and increased crime rates, run deep. Dan Cadman of the Center for Immigration Studies is concerned that they spread crime. Reihan Salam of the Manhattan Institute wrote that "an ongoing [immigration 1 influx will tend to reinforce ethnic enclaves and endogamous marriage, both of which impede assimilation." Salam devoted a few pages of his book--Melting Pot or Civil War? A Son of Immigrants Makes the Case Against Open Borders--to the pernicious effects that ethnic enclaves have on assimilation, ultimately concluding, "but is this any reason to be alarmed? The answer is yes." Salam's exhortation to panic was outdone by the National Review Institute's Andrew McCarthy, who thinks that Muslim enclaves are going to overwhelm European legal institutions and impose Sharia law in the wider society.
Beyond the writings of pundits, there is expansive academic literature on the effects of ethnic enclaves. One of the biggest disputes within the literature is the definition--what exactly is an ethnic enclave? Some studies define them as those communities in which immigrants cluster in residential housing, like George J. Borjas (1995) and Jimy M. Sanders and Victor Nee (1989). Other studies define enclaves as segregated workplaces comprising a specific ethnic group, like Alejandro Portes (1989).
The ethnic enclave literature also suffers from data limitations. Lower-skilled immigrants tend to cluster in enclaves, while higher-skilled immigrants find work outside the enclaves. Separating an immigrant's workplace and personal residence is crucial to account statistically for all members of an ethnic enclave. Many studies control for this factor, but there are other factors, such as immigrants' legal status and the educational quality and regulatory restrictions within the enclave that rarely are controlled for. Although we must be wary of overcontrolling, proper statistical analysis must have enough controls to identify...