California’s steady rise in high school graduation rates has been a highly visible and well-publicized education success story. As Tom Torlakson, the state superintendent of public instruction, put it proudly a year ago: California’s “graduation rates have gone up seven years in a row.” But much of that progress, supposedly enough to cut the percentage of students not graduating from high school by more than a third, could be a sham.

That’s because of the less-visible, and poorly publicized, numbers of California students who graduate by taking “credit recovery” courses — makeup classes that let students who fail in a subject get back on track to graduate.

I analyzed the first available national data on participation in these programs, which show that in 2016, California’s participation was far above the national average, with 1 in 10 high school students taking at least one credit recovery class. The data are not divided by grade level, but because most students take these makeup classes in the run-up to graduation, participation is probably closer to 1 in 5 12th-graders. Unfortunately, many of those students will get passing grades for paltry amounts of effort.

Credit recovery courses vary from district to district, and school to school. They can include traditional summer school, but today most programs are offered online or in “blended” formats that combine online work and teacher support. In the most suspect cases, districts adopt an “anything goes” approach, giving rigor short shrift so long as graduation rates keep rising.

A Los Angeles Times story last year detailed potential problems with the credit recovery programs at LAUSD. It pointed out that the district offers nearly a dozen credit recovery options, with no “across-the-board standards” for what was offered or how they would be taught and graded. The district defends the classes as “rigorous and effective,” but anecdotal evidence raises doubts. A Garfield High student turned an F into a C in just a week, and a student at Fremont High “pre-tested” out of most of the units in her English credit recovery course, completing the rest with just a single writing assignment.

Such reports, echoed across the country, make the dangers of low-quality credit recovery easy to see. However, since the design and delivery of the classes aren’t standardized, and they aren’t being carefully monitored or widely assessed, too little is known about their quality or how widespread low-quality programs are in California.

The participation rates I researched show a third of California high schools report no credit recovery programs at all. But that means other schools with sky-high credit recovery participation rates are bringing up the state’s average, and there are good reasons to believe the higher the participation at a school, the lower its program’s quality.

Students who fail a class need more direct teacher support to pass makeup courses that are both abbreviated and rigorous, but most credit recovery programs lean heavily on online instruction specifically to minimize staffing needs. The teachers who supervise computer-driven credit recovery in multiple subjects are also unlikely to be the schools’ best. Such deficiencies are only amplified dramatically by high student participation.

In California, 1 in 3 high schools is cause for concern, with participation rates at least 50% higher than the national average. Quality problems are not only more likely at those schools, but they also will affect more students — 17% of California schools account for 57% of the state’s credit recovery participants.

Unfortunately, quality problems are compounded by an equity problem. California high schools with the highest credit recovery participation have far more poor and minority students than other schools. They also have more chronic absenteeism, higher suspension rates, lower proficiency in reading and math, and lower graduation rates. The one seemingly bright spot for these schools — larger graduation rate increases than at all other schools, for five years in a row — has to be viewed with suspicion. It may only corroborate a mirage of progress in schools where credit recovery programs have turned from second chances to graduate into a second and inferior track to graduation.

California’s addiction to credit recovery isn’t an adequate response to students who fail classes and can’t graduate. It can hurt those who take them as an easy way out, and it hurts hardworking students who put in the work only to receive the same diploma as those who haven’t made the grade. The cure could start with basic transparency, by adding each school’s credit recovery participation to the California School Dashboard, the state’s online school grading tool. Failing to report this data maintains perverse incentives, giving districts the payoff for graduation rate gains, even when progress is often hollow.

Done well, credit recovery programs can give students rigorous second chances to meet expectations. However, a patchwork of unexamined “makeup” classes isn’t going to serve the state or its struggling students well.