Less than a full school year since it started, educators are already seeing "phenomenal results," Rodriguez said.
Students are able to cover more in a shorter amount of time than they would in a traditional classroom setting, he said.
They are grouped for half-hour blocks three times a day.
Confidence is also up while negative behaviors are down, he added.
"It has very positive side effects," Rodriguez said. "It shows kids that everyone does care, that they're there to help them."
Eighth-grader Jennifer Cortes, 14, said she couldn't believe a principal would come into the classroom and take his time to help students.
It showed her that the teachers and administrators want her to succeed, she said.
The school serves nearly 750 seventh- and eighth-grade students, more than 80% of whom come from low-income families. More than half of the students are English learners.
The school already had before- and after-school tutoring and an intervention program in place during the school day, but about 25% of students were still consistently failing, Rodriguez said.
It was that quarter of the student body not making it that spurred educators to try something different and more intensive.
The key to giving kids what they need to succeed is finding out exactly what they didn't know by assessing every student, Rodriguez said.
"We diagnose what exactly it is that these kids need," he said.
The students aren't told what grade level they are at, but what skills they are struggling with, he said.
Eighth-grade student Carlos Castaneda, 14, said his confidence has gone up with his reading skills and fluency.
Although he originally thought breaking into groups would be a fun break from class, Carlos said he was surprised by how useful it has been.
He said he gets more teacher attention during the time and doesn't feel self-conscious about reading aloud because everyone in his group struggles with the same issues.
His confidence in reading aloud has also spilled over into his other classes, because his teachers can understand him better.
"I feel like I want to learn more to surprise them," he said. "They're helping me and I want to pay them back."