The United States could save about $45 billion a year by cutting the high school dropout rate in half, according to a new study. Estimating the potential savings—which the researchers put at $127,000 per new graduate—is the easy part. Identifying effective interventions is more difficult, but the study from Columbia University’s Teachers College focuses on five strategies that can help produce the estimated savings.

More than 700,000 of this country’s 20-year-olds are high school dropouts. The savings from cutting that number for future 20-year-olds, the study reports, come from higher tax revenues as well as lower government spending on health, crime and welfare. The authors add that their savings estimates are conservative be-cause they don’t include private benefits, such as higher earnings. The savings also don’t include benefits such as reductions in juvenile crime and teenage preg-nancy because they can’t be adequately quantified.

The five interventions, all of them supported by rigorous scientific evaluations, are:

■ the Perry Preschool program in Ypsilanti, Mich., which included home visits, parents meetings and small child-to-teacher ratios;

■ Chicago’s child-parent center program, a public school-based initiative that includes parental involvement, community outreach, and health and nutrition services;

■ First Things First, a comprehensive reform program that includes small learning communities, family advocates and improved instructional approaches;

■ class-size reduction, with sizes reduced from 25 to 15 students in grades K-3, based on the results of Project Star in Tennessee; and

■ teacher salary increases of 10 percent for all grades, K-12.

In addition to these specific approaches, the authors identify several common characteristics of effective interventions that could prove beneficial in reducing dropout rates when incorporated in other programs. These include small-size schools, high levels of personalization, high academic expectations, strong counsel-ing, parental engagement, extended learning time, and competent and appropriate personnel.

The study’s economic analysis shows that each new high school graduate yields a public benefit of $209,000, while requiring an overall investment of $82,000. The net benefit is 2.5 times higher than the costs. That means an even smaller reduction in dropout rate could bring substantial savings; a 20 percent decrease (140,000 fewer dropouts), for example, would save $18 billion a year.

“What makes this study so powerful is that it has been conducted by economists of the first rank, using sophisticated approaches that, if anything, underestimate the potential value of investing up front in education,” says former West Virginia Gov. Bob Wise, president of the Alliance for Excellent Education, who spoke at a gathering marking the report’s release. “At a time when Congress is re-evaluating the effectiveness of the federal No Child Left Behind Act, [the report] provides lawmakers with a valuable tool to make the case that schools must be given more capacity to improve the achievement of their students.”

The report includes specific figures on how much the different interventions cost, ranging from $2,900 per student for teacher salary increases to $13,100 for class-size reduction, as well as the number of extra high school graduates the intervention would be expected to produce if it were given to 100 students. Those second figures range from five graduates for salary increases to 19 for the Perry Preschool program.

Clearly, interventions can be even more effective if they can be targeted to students who are the most likely to drop out, the report says, because the resources are spread more thinly—or a bigger investment is required—if they target an entire school.

Despite the bottom-line focus on dollar savings, the authors conclude, good public policy is about much more than money. “A society that provides fairer access to opportunities, that is more productive and with higher employment, and that has better health and less crime is a better society in itself,” they write. “It is simply an added incentive that the attainment of such a society is also profoundly good economics.”

The complete study is available at www.cbcse.org .