With a postsecondary credential essential to finding a good job but the cost of college beyond the means of many families, a growing number of high schools are offering their students a powerful head start on higher education. About 1.3 million U.S. teens participate in dual enrollment, up from 680,000 when the century began. Critics worry that this trend could lead to an erosion of college standards, but the evidence to date has been entirely positive. Researchers have found that dual enrollment has strong effects on high school graduation, college enrollment, and college completion, particularly for low-income youth and others underrepresented in higher education.