Hundreds of Houston-area elementary students at campuses with staggering, double-digit retention rates each year are forced to repeat the same grade level - a red flag that experts warn could have detrimental long-term effects on children.

Roughly 75 campuses in the region held back more than 10 percent of students in at least one elementary grade level in the fall of 2015, far above the statewide averages. Some schools had retention rates above 25 percent.

Educators blamed the retentions on poor attendance, new grading systems, sub-par reading or math skills, or failure to attend summer school.

"It's a real disservice to those kids," said Robert Sanborn, CEO of Children at Risk, a Houston-based advocacy group. "We're basically saying, 'You're just going to repeat it, sorry, and we're going to go ahead and doom you at the same time to a poor academic life.'"

Although high retention rates affect a wide array of schools - including some with A ratings from Children at Risk - schools with double-digit retention rates had higher percentages of minority and economically disadvantaged students, according to a Houston Chronicle analysis of a decade of state education data from 10 school districts.

Research shows that students who are held back are more likely to struggle socially and drop out of high school, making retention a last resort for many educators. The Houston Independent School District decided earlier this year to stop using failing scores on the state's standardized test as a reason to hold students back.

But critics question whether schools could be retaining students to give them more time to prepare for high-stakes standardized tests.

Paul Thomas, an associate professor of education at Furman University in South Carolina, said data for the local districts analyzed appear to match a model used in other states where kids are held back in hope of raising future test scores.

"There is some evidence that grade retention in the short term will boost test scores," he said. "The problem with that is that the research also shows that that disappears over time."

Trusting the teachers

More than 60 elementary schools in Houston, Pasadena, Aldine and Alief ISDs had at least one grade level with retention rates exceeding 10 percent, according to the 2015-2016 Texas Academic Performance Report, which measures students held back for the fall of 2015, the most recent year for which data is available.

"That is a tremendously high number to fail and bring back to repeat a grade level," said Houston Federation of Teachers President Zeph Capo.

At Burbank, Gregg and Field elementaries in Houston ISD, for example, retention surpassed 20 percent in the third grade, a number that one expert called "astronomical." Statewide, just 2 percent of third-graders were held back that year. Districtwide, it was just 4 percent.

Burbank Elementary administrators questioned the data, saying it didn't reflect their final retention numbers, while officials at Field Elementary in the Heights said much of their retention stemmed from refusal to attend summer schools.

Whatever the numbers show, Field parent Patty McGrail said she is confident the school is making the best decisions it can. "If they feel the need to hold a kid back, I trust that," she said. "I trust my child being there because I know the teachers there."

Other schools in the district cited retention requests from parents, an influx of new teachers, reading deficits and high student mobility rates as reasons for holding students back, according to Capo.

Sarah Becker, an active parent in Houston ISD, said the high retention rates could be related to the state's under-utilization of special education, as revealed last year in a Houston Chronicle investigation.

"These are kids who should be referred for special ed, and they're not getting referred," she said. "They'll just try retention even though it's not a good intervention and there's pretty much no research to support that idea. We should be referring them to special ed, but we're not."

Closing the gaps

In Pasadena ISD, where 13 schools had double-digit retention in the latest TAPR, two principals attributed the issue to a change in grading systems.

"A lot of the retention rate changes were the year we did the first standards-based report card," said Red Bluff Elementary Principal Tammie Hinton. "It was no longer an A-B-C-D-F program. In some schools it made their retention rate go up."

At South Belt Elementary, Principal Candy Howard saw that same trend, but added that the double-digit retention at her school failed to reflect the actual number of kids held back after finishing summer school.

In some cases, she said, the high retention rates could reflect staffing weaknesses.

"If you have 20 percent of the campus being retained, that's not about the students," she said. "That's about the teachers."

Alief ISD, which also had a number of elementaries with double-digit retentions, refused multiple requests for comment.

In Aldine ISD, 19 elementary schools had double-digit retention rates in at least one grade level, according to the TAPR data. More than 27 percent of second-graders at Calvert Elementary repeated the grade level, a problem that Principal Cheryl LeFleur attributed to high rates of absenteeism.

"Those with excessive absences were found to have many skill gaps in both reading and math," she said. "Closing the skills gaps alone took almost the entire year after kindergarten and first grade.

Rather than maintaining a solid foundation and preparing students for the next grade, we needed to provide many interventions to those second-grade students in order to attempt to close the skills gaps."

First grade historically has the highest retention rate in Texas elementary schools at just over 4 percent.

Finding solutions

School officials are adamant that students are not being retained to boost test scores.

"That would be ethically wrong," said Hinton, the Pasadena principal whose school has stayed under a 10 percent retention rate across all grades in the latest data. "I don't know any person that I have worked with who would retain a child to make their test scores higher," she said. "That actually makes me sick to my stomach."

Sanborn suggested that school districts need to implement early interventions to students who are behind, including tutoring, extended school days or full-day pre-kindergarten, rather than tossing taxpayer dollars at retention.

"We spend a lot of money in the state of Texas repeating these grades when that money would significantly be better spent on full-day pre-K," Sanborn said.

In addition, struggling students should be identified in the first month of school and worked with immediately, rather than waiting and allowing them to fail at such high rates. They should be paired with tutors and given extra help.

"When we see schools that are doing this right, they identify kids pretty quickly. Immediate intervention - we know that's a best practice," he said. "When you fail a child or you retain a child, the chances of them getting back on their feet and doing well are slim. If you retain, it's like a black mark on this child."

Matt Dempsey and Jaimy Jones contributed to this report.