This report introduces a quantitative index that measures the degree of similarity between native- and foreign-born adults in the United States. It is the ability to distinguish the latter group from the former that we mean when we use the term “assimilation.” The Index of Immigrant Assimilation relies on Census Bureau data available in some form since 1900 and as current as the year before last. The index reveals great diversity in the experiences of individual immigrant groups, which differ from each other almost as much as they differ from the native-born. They vary significantly in the extent to which their earnings have increased, their rate of learning the English language, and progress toward citizenship. Mexican immigrants, the largest group and the focus of most current immigration policy debates, have assimilated slowly, but their experience is not representative of the entire immigrant population.
Collective assimilation rates are lower than they were a century ago, although no lower than they have been in recent decades. And this is true despite the fact that recent immigrants have arrived less assimilated than their predecessors and in very large numbers. In addition to country of origin, the Index categorizes groups on the basis of date of arrival, age, and place of residence. Some groups have done far better or worse than the Index as a whole; Assimilation also varies considerably across metropolitan areas.
Here are some of the Index's significant findings:
- The degree of similarity between the native- and foreign-born, although low by historical standards, has held steady since 1990. Assimilation declined during the 1980s, remained stable through the 1990s, and has actually increased slightly over the past few years.
Beyond presenting a snapshot of the degree of similarity between the native- and foreign-born, the assimilation index can be used to track the progress of immigrants who arrived in the United States at a common point in time. This simple extension shows that the relative stability of immigrant assimilation since 1990 masks two important and countervailing trends.
- Newly arrived immigrants of the early 21st century have assimilation index values lower than the newly arrived immigrants of the early 20th century. Growth in the immigrant population usually lowers the assimilation index because newly arrived immigrants drag down the average for the group as a whole. This phenomenon can be seen between 1900 and 1920 and again in the 1980s. The stability of the assimilation index since 1990 is therefore remarkable in light of the rapid growth of the immigrant population, which doubled between 1990 and 2006.
- Immigrants of the past quarter-century have assimilated more rapidly than their counterparts of a century ago, even though they are more distinct from the native population upon arrival. The increase in the rate of assimilation among recently arrived immigrants explains why the overall index has remained stable, even though the immigrant population has grown rapidly.
- Yet the current level of assimilation remains lower than it was at any point during the early 20th century wave of immigration.
The assimilation index can be decomposed along several other dimensions. The overall, or composite, index is based on a series of economic, cultural, and civic factors. These sets of factors can be examined in isolation to produce three component indices. The economic index compares the labor force, educational attainment, and home ownership patterns of the foreign- and native-born. The cultural index focuses on English-speaking ability, marriage, and childbearing patterns. The civic index examines naturalization rates and compares the military service patterns of the foreign- and native-born. Separate analysis of these three dimensions of assimilation reveals that they do not increase in lockstep as immigrants spend more time in the United States.
- Economic and civic assimilation often occurs without significant cultural assimilation. It is common for immigrant cohorts to naturalize and enjoy integration into the economic mainstream without posting many gains along cultural dimensions.
- Immigrants who arrived in the United States after 1995 are culturally assimilating more rapidly than their predecessors. The increased rate of overall assimilation shown by cohorts of recent arrivals can be traced in part to this pattern of relatively rapid cultural assimilation.
The assimilation index can be computed for individual country-of-origin groups, or for sets of immigrants who live in a particular city or region. Disaggregation by country of origin reveals important differences in the experiences of immigrants born in different parts of the world.
- Immigrants from developed countries are not necessarily more assimilated. Immigrants born in Korea, which the World Bank classifies as a high-income country, have a collective assimilation index value lower than that of immigrants from Cuba or the Philippines, which are classified as low-income countries. Several factors can explain this pattern, among them the fact that immigrants from developed countries do not necessarily become naturalized citizens more rapidly than those from the developing world. The United States often attracts immigrants who belonged to the economic elite of their origin country.
- Immigrants from Vietnam, Cuba, and the Philippines enjoy some of the highest rates of assimilation. However, these groups assimilate more rapidly in some respects than others. For example, they are far more assimilated economically than they are culturally. Curiously, all of the countries mentioned have experienced U.S. military occupation.
- Mexican immigrants experience very low rates of economic and civic assimilation. Immigrants born in Mexico, particularly those living and working in the United States illegally, lie at the heart of many current debates over immigration policy. The assimilation index shows that immigrants from Mexico are very distinct from the native-born upon arrival and assimilate slowly over time. The slow rates of economic and civic assimilation set Mexicans apart from other immigrants, and may reflect the fact that the large numbers of Mexican immigrants residing in the United States illegally have few opportunities to advance themselves along these dimensions.
- Mexican immigrants experience relatively normal rates of cultural assimilation. Recent cohorts of Mexican immigrants have increased their rate of cultural assimilation just as immigrants born in other nations have done.
A specialized version of the assimilation index can be computed for foreign-born adolescents and young adults who came to the United States as young children and received their formal education exclusively in this country. This version of the assimilation index also reveals interesting patterns.
- The foreign-born children of immigrants continue to bear a strong resemblance to their native-born counterparts. Although many members of this group are not naturalized citizens, they are difficult to distinguish from the native-born along other dimensions.
- Immigrant children born in Mexico are more distinct than immigrant children born in other foreign nations. This distinction is most obvious in terms of comparative naturalization rates, but extends to other dimensions as well. Mexican adolescents are imprisoned at rates approximately 80 percent greater than immigrant adolescents generally.
- Naturalization rates among the foreign-born children of immigrants have been increasing. In this respect, the behavior of foreign-born, domestically educated immigrants resembles that of their parents educated abroad.
Disaggregation by metropolitan area reveals widely varying rates of assimilation, due largely to the different combinations of immigrant groups that reside in each and the different characteristics of those groups.
- Polyethnic New York City, which still attracts large numbers of European immigrants, has the second-highest assimilation index value among the metropolitan areas defined.
- San Diego, despite its proximity to the Mexican border, has the highest.
The methodology used to compute the assimilation index is outlined in the report and reviewed extensively in a more technical appendix. The method has been designed to take advantage of more than a century’s worth of historical data on the status of immigrants in the United States, made available to the public by the United States Census Bureau, and to provide the opportunity for annual updates.
The assimilation index points to marks of success, to encouraging recent trends, and also to areas of concern. Within these areas of concern, the index provides some insight into the nature of the problem and the universe of appropriate potential policy responses. It is important to note, however, that this report neither proposes nor endorses any policy responses. Its sole purpose is to present information in a manner useful to concerned citizens and policymakers who hope to make informed decisions regarding the proper course of action.