Online credit recovery classes, where students who fail a course on their first attempt retake it online, are growing in Georgia and nationally.

In Gwinnett County, Georgia's largest school district, enrollment in online credit recovery classes tripled in the past three years.

Educators say online credit recovery courses can keep students from dropping out. They can work through the online lessons at their own pace and on their own schedule. And some students say they prefer online courses to traditional classrooms.

But some teachers and students say the largely unregulated courses do more to boost graduation rates than help students learn material they didn’t get the first time around, leaving them with high school diplomas but without the skills they need to succeed in college or at work.

Last year, more than 700 Gwinnett County students took one or more online credit recovery classes. Every one of those students passed, according to data obtained under the Georgia Open Records Act. Yet for courses requiring students to take state tests, less than one in five mastered the material, state test results show.

Statewide, about 90 percent of Georgia students who took one of these courses last year in subjects covered by state tests passed the course itself. But an Atlanta Journal-Constitution analysis of results of the state-required tests found only about 10 percent of them were proficient in the subject.

Gwinnett actually has one of the higher proficiency rates in the state among online credit recovery students, according to state data. (About 50 districts didn’t report any students in online credit recovery courses.)

Gwinnett officials said it’s not surprising that so many of their students passed their classes. Only students who fail a class by 10 points or less on their first attempt are allowed to retake it online.

“We feel like those students are close to passing the course the first time around and just needed some more time,” associate superintendent Jonathan Patterson said. The high passing rate shows “we’re doing what credit recovery is intended to do.”

Test scores for some of those students were below “proficient,” but high enough to show they had learned some course material, Gwinnett officials said in a written statement. Those students “have shown improvement and have learned more of the content necessary for the course.”

>>Read more: Retaking classes online: ‘Awful if someone really wants to learn’