Descendents of Mexican immigrants in the U.S. may be making better socioeconomic progress than many studies indicate, according to research published in the April issue of The Journal of Labor Economics.

A large body of recent research has raised concerns about the economic progress of Mexican Americans. Third and fourth-generation Mexican Americans are no more likely to graduate high school than second-generation Mexican Americans, the studies show. Wages appear to stagnate after the second generation as well.

But these studies share a common problem that skews their results, according to economists Brian Duncan (University of Colorado, Denver) and Stephen Trejo (University of Texas, Austin).

"Almost without exception, studies of later-generation Mexican Americans rely on ethnic self-identification to identify the population of interest," Trejo said.

That's a problem because many immigrant descendents may not identify themselves as Mexican American on surveys or census forms. This is especially true for the children of Mexicans who intermarry with non-Mexicans. And according to Duncan's and Trejo's research, the children of intermarried Mexicans tend to have substantially higher educational attainment and better English language skills.

"In effect, through the selective nature of intermarriage and ethnic identification, some of the most successful descendants of Mexican immigrants are not included in intergenerational studies," Trejo said.

To see how much this loss of ethnic identity might skew progress research, Duncan and Trejo used data from the Census Bureau's Current Population Survey. The CPS captures information about where each person and his parents were born, and it allows information to be matched across all persons living in the same household. For children living with both parents, the CPS data therefore reveal how many parents and grandparents were born in Mexico, which provides a more objective way to identify Mexican immigrant descendents. The researchers could then compare educational attainment among objectively identified and self-identified Mexican descendents.

They found that about 30 percent of third-generation Mexican youth fail to self-identify as Mexican. Moreover, the high school dropout rate of these youth is 25 percent higher when the sample is limited to those who self-identify as Mexican.

"This is direct evidence that ethnic attrition is substantial and could produce significant downward bias in standard measures of attainment that rely on ethnic self-identification rather than objective indicators of Mexican descent," Trejo said.

Prior intergenerational progress studies are often cited as evidence that Mexican immigrants and their descendents are failing to assimilate in American society. But Duncan's and Trejo's finding paints the opposite picture.

"Many Mexican immigrant descendents are assimilating to such an extent that they fade from empirical observation," Trejo said.

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More information: Brian Duncan and Stephen J. Trejo, "Intermarriage and the Intergenerational Transmission of Ethnic Identity and Human Capital for Mexican Americans." The Journal of Labor Economics 29:2 (April 2011).