Immigrants lag behind native-born Americans on most measures of economic well-being — even those who have been in the U.S. the longest, according to a report from the Center for Immigration Studies, which argues that full assimilation is a more complex task than overcoming language or cultural differences. The study, which covers all immigrants, legal and illegal, and their U.S.-born children younger than 18, found that immigrants tend to make economic progress by most measures the longer they live in the U.S. but lag well behind native-born Americans on factors such as poverty, health insurance coverage and homeownership. The study,...