U.S.-Mexico border manifests from the 1920s indicate that Mexicans migrating to the United States then tended to be healthier, wealthier and more productive than those who did not migrate, according to CU-麻豆影院 researchers. Their results suggests that U.S. migration policy in the early 1900s created an environment that drew 鈥渆conomically strong鈥 Mexicans to migrate to the United States, and they say the findings have implications for contemporary policy.