AUSTIN — High school students who took dual credit classes graduated with a college degree about a year faster than students who didn't, according to data presented to Texas lawmakers Wednesday.

Based on a cohort of students who started college in 2011, students with dual credit graduated college in 4.3 years on average compared to students without dual credit. Those students graduated on average in 5.1 years, Texas Commissioner of Higher Education Raymund Paredes told senators during a hearing in the state Capitol.

Dual credit programs allow students to take college-level courses while in high school, at a free or drastically reduced cost to the student. Education officials have touted the program as a way to put more poor and minority students on the college track.

Texas's dual credit enrollment program has more than doubled in the past decade, increasing from 64,910 high school students taking at least one college credit course in 2007 to 151,669 in 2017.

The program's success was also reflected in graduation rates, with the statewide four-year rate for dual credit students at 41 percent, compared to 27 percent for non-dual credit students. The six-year graduation rate for dual credit students was 69 percent, compared to 56 percent for other students.

Senators who scheduled the hearing to learn more about the program's results welcomed the news.

Source: Texas Higher Education Coordinating Board

"What we know is that there is a tangible, measurable benefit to taking dual credit classes," said Sen. José Menéndez, a San Antonio Democrat.

But one lingering concern among education leaders and lawmakers it that the program is more likely to benefit white, affluent students who were already college bound.

Last year, poorer students made up only 37 percent of students enrolled in dual credit classes, an increase from 25 percent in 2007. Hispanic students make up 51 percent of all students in high school but only 46 percent of the students taking dual enrollment classes. Black students made up only 7 percent of those taking dual credit classes.

"We know that oftentimes those students are less encouraged at home to go to college, and consequently they might be less interested in dual enrollment," Parades said of low-income students.

Lawmakers also asked whether dual credit classes are equally as rigorous as the same credit taken at the college level.

University of Texas Associate Vice Chancellor David Troutman said the school began investigating the issue after hearing anecdotally from faculty about concerns that the students with dual credits weren't academically prepared for more advanced classes.

But a deeper dive into outcomes from dual credit students produced good news.A review of UT students from 2010 to 2015 found that students were two times more likely stay in school after their first year if they started with dual credits. They also were three times more likely to complete school in four years if they started with even one dual credit.

The university also reviewed students' grades in advanced subjects like chemistry and calculus comparing grades from students who took their core math and science classes through a dual credit program against those who took the class at UT.

"There were very few differences in grade performance," Troutman said, calling the finding "exciting." "They are performing well in their upper division classes."

Another study, released in July by the American Institutes for Research, evaluated performance outcomes for two courses and found that rigor for dual credit programs matched the courses taught at the university.

But Trey Miller, the principal researcher on the study, cautioned that it looked at only two courses. He said more research should be done to ensure all dual credit courses are meeting academic standards required for college.