Students at some Colorado online schools move around a lot. A bill to track them better advances.

Lawmakers and education officials will take a closer look at turnover in online schools under a bill that passed the Senate Friday. While online schools educate a relatively small portion of Colorado students, enrollment is growing, and some of these schools have among the highest mobility rates in the state.

But there’s disagreement over how much detail the information collected should include. Senate Bill 129 passed in a 21-14 vote, with all but two Republicans opposing it.

State Sen. Tammy Story, the Conifer Democrat sponsoring the bill, wants to see more accountability for what happens to students in online schools. She said the measure will require reporting of the grade level students are at when they enter online schools and when they leave, in addition to whether they graduate, transfer to another school, or pass a high school equivalency exam.

But state Sen. Paul Lundeen, a Monument Republican, said he would like to see information about how students progress during their time in online schools.

“In public education the online environment is one of those places where we serve students who are struggling in the traditional environment,” Lundeen said during Thursday’s brief debate on the measure. “Understanding the growth that we’re getting … becomes very important.”

He said policy makers need to know how students are performing in literacy and math. Merely tracking grade levels isn’t enough.

“That information is helpful but it’s not really precise enough to get at the issues I was raising,” Lundeen said.

But Story said tracking at what grade level students are performing at entry and exit would give enough information on student growth.

It’s true that turnover is higher among online schools than at traditional schools. Chalkbeat Colorado received school-by-school turnover data from the Colorado Department of Education for the 2017-18 school year.

Turnover was about 12 percent among brick-and-mortar schools, compared with 31 percent at the state’s 44 online schools.

That’s an improvement from past years, when a 2011 Chalkbeat and I-News Network investigation determined that half of online school students left within a year of enrolling during the 2008-09 school year.

Problems arise, that series noted, when online schools receive full-year funding for a student who may attend for only a few months. If a student transfers to a traditional brick-and-mortar school, the funding doesn’t follow them.

That’s a problem in a state where school funding is limited.

During the 2017-18 school year, five online schools were in the top 20 when it came to mobility rates. Mobility rates at the 20 highest-turnover schools ranged between a low of nearly 64 percent APS Online School to a high of 100 percent at one Jefferson County vocational school that began with 24 students.

Six of those top 20 schools, including two online schools, had fewer than 50 students during the school year.

Colorado Department of Education officials caution that mobility rates vary depending on a variety of factors. Some schools may actually be geared toward students who move frequently, while others may be located in areas with high mobility.

Mobility rates aren’t used in evaluating school effectiveness in Colorado, and there’s no standard benchmark for the measure.

Only nine of the 44 online schools had mobility rates below 20 percent in the 2018 school year. Eight had mobility rates of 50 percent or higher. The rest were between 20 percent and 49 percent.

Hanover Online Academy, for instance, had six of seven students leave. Center Virtual Academy saw 13 of 18 students exit. And 90 of 114 students left Paragon Learning Center.

Executives at K-12 Inc. called for more detailed tracking of a student’s credit status and progress during the time they’re at a school, instead of simply whether they graduate or not in a threepart series for Education Commission of the States in 2017.