A student searches for her family after the graduation ceremony at Stonewall Jackson High School in Manassas, Va. (2015 photo by Gabriella Demczuk /For The Washington Post )

U.S. high school graduation rates are soaring. President Obama announced in October that the 2014-2015 rate was up to 83 percent in a fifth straight record-setting year. The D.C. public schools’ increase was the greatest anywhere, from 53 percent to 69 percent.

Sadly, as impressive as these numbers seem, there is no research indicating they reveal any learning gains in our high schools. Because of an accelerating use of a shortcut to graduation called credit recovery — used by 88 percent of school districts — most if not all of this much-publicized high school improvement might be an illusion.

I asked Russell Rumberger, a leading expert on high school dynamics, what he thinks of credit recovery. In many schools, these quick fixes allow students to substitute a few weeks of work online for a course that usually takes months in a classroom.

Rumberger said research on credit recovery generally “suffers from poor designs, which means it’s hard to draw strong conclusions and most research is carried out in higher education, not K-12.”

The most relevant data Rumberger found compared student experiences in online and in traditional classroom versions of Algebra I during summer school sessions for 1,224 Chicago students who had previously failed the course. The students in the online course found it more difficult and had more negative attitudes about math than the students who were face-to-face with a teacher. The online students also had lower assessment scores than those in the traditional course. Both groups had similarly poor records in subsequent math courses.

The crucial difference between this study and what often happens in high schools is that the online and face-to-face students in the Chicago study by the American Institutes for Research spent the same amount of time in the course. Online credit recovery courses can “require less time and involve less work than a regular classroom course,” said Rumberger, a professor at the University of California at Santa Barbara. He wrote the 2011 book “Dropping Out” and directs the California Dropout Research Project.

That isn’t often mentioned when state and local officials announce their latest graduation rates, such as the impressive 87 percent in Maryland and 91 percent in Virginia. Before educators get too excited about the results from credit recovery, they need to assess how much those students have learned in a few weeks compared with those who spend months in class.

A report by the International Association for K-12 Online Learning says “too often credit recovery ‘solutions’ have lowered the bar for passing.” It recommends valid tests of competency before awarding credit, something D.C. officials say they hope to do. Arlington uses credit recovery usually for students well past age 18 or who have had trouble with the law.

To Rumberger, measuring success by graduation rates is highly suspect.

“Students who are passing classes with a ‘D’ grade probably aren’t learning much and are likely not prepared for college and careers,” Rumberger said. “Some research suggests that students need a high school GPA of 2.5 to be ready for college (i.e., don’t need remediation) and have good labor market prospects. So we may be graduating lots of students who are not adequately prepared for the future.”

But until we find ways to engage such students in their classes, credit recovery might be the only way, practically and politically, to get them the high school diplomas they need to get into the workplace. A significant number of 17- and 18-year-olds are so disenchanted with high school that making them stay would be painful and counterproductive.

Credit recovery graduates are better off learning about the working world in real jobs, which they are more likely to get if they have diplomas. Meanwhile, we should restrain our enthusiasm about our rising graduation rates. Those numbers aren’t worth the headlines they are getting. We need to find ways to improve teaching and learning for all students, before they decide high school is not worth the time and trouble and escape any way they can.