During the first seventy years of the twentieth century, the high school graduation rate for American teenagers skyrocketed from six percent to eighty percent. This remarkable boost in rates of high school graduation fueled the national economic growth that produced rising incomes for most American families. But recent trends in high school graduation have been more complicated and puzzling, as my research seeks to describe and explain.

The Measurement of High School Graduation Rates

In interpreting statistics on high school graduation rates, it is important to keep several things in mind. First, one in ten black and Hispanic students who graduate from high school take more than four years to do so, so ethnic and racial graduation rates look more similar if we look after six years. Second, estimates of high school graduation rates, especially for Hispanics, depend on how we treat recent immigrants, the majority of whom come from Latin America. Half of those coming from that region after the age of 11 fail to graduate from high school. Finally, researchers have to decide how to classify recipients of the General Educational Development credential, whose numbers grew enormously between 1970 and 2000. Such recipients are treated as non-graduates in the estimates of graduation rates reported here, and recent immigrants are excluded.

With those adjustments, four key patterns stand out:

• Over the last three decades of the 20^th century, U.S. high school graduation rates stagnated.
• There are substantial gaps in graduation rates for young people from different racial and ethnic groups and socioeconomic backgrounds.
• In recent decades, girls have become substantially more likely to graduate than boys, and this gender gap is especially large among blacks and Hispanics.
• In the first decade of the 21^st century, the overall high school graduate rate grew substantially, by six percent – a shift from the previous stagnation.

Explaining Late-20^th Century Stagnation

Average wages for male and female high school dropouts fell compared to wages for graduates between 1980 and 2000 – so why didn’t the higher rewards for high school diplomas cause the graduation rate to go up? Several factors seem to have been at work. Many students, especially minorities and those from low-income families, entered high school without appropriate reading and mathematical skills and faced high costs in time and anxiety to complete all requirements for high school graduation. During the same decades, many states increased standards, both by increasing the number of core courses needed for high school graduation and by requiring that students pass exit examinations in English and mathematics. A number of studies show that this raised hurdles for students with weak skills, even as alternatives such as the General Educational Development credential became more available to teenagers who dropped out of high school.Average wages for dropouts fell compared to wages for graduates between 1980 and 2000—so why didn’t the higher rewards for high school diplomas cause the graduation rate to go up?

Making Sense of Social Gaps

Various factors contribute to substantial social gaps in high school graduation rates.

• Explaining racial, ethnic, and income gaps. Children from minority groups and low-income families enter kindergarten with weaker skills on average than non-Hispanic white children from more affluent families. Gaps persist during the elementary- and middle-school years, causing many of the same youngsters to enter high school with weak skills. Due to residential segregation, such students are likely to attend high schools with equally unprepared peers and unstable teaching staffs. Tougher requirements also reduced their graduation rates.
• Explaining the gender gap. The increasing percentage of children growing up in single-parent families has contributed to the gender gap in high school graduation rates. In families led by mothers on their own, boys do less well than girls and often develop behavior problems that contribute to school failure.

Explaining the Recent Turnaround

Scholars cannot fully explain increases in high school graduation rates between 2000 and 2010 – including the especially large increases for black and Hispanic students. But evidence from the National Assessment of Educational Progress provides crucial clues. Between 1995 and 2010, the performance of eighth graders on reading and mathematics tests improved substantially, so more students entered high school with the skills needed to complete their work. And why did eighth graders do better? Maybe it was because schools were improving overall, but it is equally possible that the children at most risk for academic failure were faring a bit better in their lives outside of school.

• Between 1980 and 2000, the fraction of American four-year-olds enrolled in preschool programs offering some instruction increased from one-half to two-thirds, so more young children likely mastered the cognitive and social skills needed for success in school.
• America’s teenage birth rate went down by 44 percent between 1990 and 2008, so fewer teenage girls dropped out and fewer babies grew up with impoverished single parents.
• Teenage arrest rates for violent offenses declined by almost 50 percent between 1994 and 2009, reducing the ranks of youths in the criminal justice system who often fail to graduate.

More to Learn

At this time, researchers have only a limited understanding of why social circumstances have recently improved for disadvantaged children, or how improved circumstances outside of school contribute to improved rates of high school graduation. The more we learn, the better the insights we can offer as public policies are designed to sustain and accelerate improvements.

Read more in Richard J. Murnane, “U.S. High School Graduation Rates: Patterns and Explanations.” Journal of Economic Literature 5, no. 2 (June 2013): 370-422.