Children who attended Louisiana’s pre-kindergarten classes consistently outperformed their state peers, and those gains have held up nine years later, officials said Wednesday.

Student achievement shot up from the 10th percentile — that means students outperformed 10 percent of their counterparts on key standardized tests — before the classes to the 50th percentile afterward, said Gary J. Asmus, director of information systems at the Picard Center for Child Development and Lifelong Learning in Lafayette.

“How long does it last?” Asmus asked. “Right now, it is at least through the eighth grade.”

Asmus and Billy R. Stokes, executive director of the center, made their comments to the House Education Committee.

How students have fared in the classes, called LA4, carries added significance because the state is about to revamp its pre-K system, mostly because of criticism that it features uneven quality, standards and availability.

Stokes noted that LA4 classes began with pilot projects in 10 school districts in 2002 and were aimed at preparing at-risk students for kindergarten.

Supporters said that, without the training, those children often fall behind their peers and never catch up.

Stokes said that, four years after attending the pre-K classes, students who did so outpaced those who did not on state tests measuring English, math, science and social studies skills.

In addition, LA4 veterans also outpaced students who did not attend the classes on eighth-grade LEAP exams, which students have to pass to move to the ninth grade.

In the English exam, 76 percent of LA4 students achieved “basic” compared with 70 percent of those who did not attend public pre-K classes, according to figures provided by Stokes and others.

In math, 74 percent of LA4 students scored “basic” compared to 65 percent of their peers, and 69 percent got “basic” on science compared with 62 percent of the non-pre-K students.

LA4 veterans also outscored students statewide.

Stokes said the gains cut across all races, ethnicities and genders.

The LA4 program provides six hours of early childhood education daily and before- and after-school care to 4-year-olds from disadvantaged families.

Nearly 32,000 students are enrolled this year.

Asmus said studies also show that LA4 veterans have lower rates of needing special education and are less likely to have to repeat a grade.

Jenna Conway, executive director of early childhood programs for the state Department of Education, said in a “highly skeptical world” officials are excited to see a pre-K program that works.

Conway said the LA4 experience will aid officials when Louisiana’s pre-K setup is revamped “so that we are not kind of reinventing the wheel community by community.”