This story is part of the KXAN Data Hub, where numbers help tell the whole story.We've created several data-driven stories and databases on topics including weather and climate, politics, education, sports and growth in Texas. Each story in the KXAN Data Hub is updated as new data becomes available. Editor's Note: The video above is from March 6, 2023, when this story was first published. AUSTIN (KXAN) — At least 108 school districts across Texas have now switched to four-day school weeks, often in a bid to prevent teacher turnover. At least 20 other districts offer a hybrid schedule, with four-day weeks for part of the year. Districts which have recently made the switch for either the 2024-25 or 2025-26 school year include Abernathy ISD, Charlotte ISD, Chisum ISD, Decatur ISD, Gladewater ISD, Greenwood ISD Hillsboro ISD, North Lamar ISD, Paris ISD and S&S CISD. Meanwhile, Jasper ISD, north of Beaumont, is returning to a five-day schedule, after having a four-day schedule since 2022. The changes mean more than 117,000 students are now in districts that use a four-day school week, based on 2023-24 enrollment numbers. A further 36,000 students are in districts using a hybrid schedule. More districts are moving to four-day school weeks: Here’s how they work Districts in all parts of the state have made the change, with the schedule proving particularly popular in rural districts in north and east Texas. In 2015, Texas lawmakers passed a bill which changed how classroom instruction was timed. Districts no longer had to provide 180 days of classes, but instead a minimum of 75,600 minutes. Requiring minutes instead of a set number of days gave districts more flexibility in how they scheduled classes. In the 2023 legislative session, lawmakers considered a bill to ban more districts from implementing four-day school weeks. Senate Bill 2368 passed the Senate but failed to make it out of a House committee. MAP: Which Central Texas districts have increased teacher pay for the 2023-24 school year? In February 2023, Crosby ISD, in Harris County just outside Houston, became the largest district in the state to adopt a four-day week. The district, which serves more than 6,700 students, approved the switch in a Feb. 27 school board meeting. The new schedule will begin in the 2023-24 school year. "Our why is simple and straightforward," Superintendent Paula Patterson said. "We want to find, recruit and retain the best teachers in the state in the classrooms for our students. This change immediately makes Crosby ISD a top destination for educators in Harris County." Meanwhile, Midlothian ISD is the largest district to adopt a hybrid schedule. The district serves almost 11,000 students just south of Dallas. The school board there approved the new calendar in a March 20, 2023, meeting. "The 2023-24 Learning Calendar allows for a student holiday approximately every three weeks aligned to grading periods," the district said in a press release. "This was intentional to allow teachers more planning and collaboration time on these days while also allowing students extended weekends with their families." Districts statewide have been struggling with teacher retention, particularly since the start of the COVID-19 pandemic. A KXAN investigation found a record number of teachers retired or resigned in the 2021-22 school year, many citing low pay and increasing workloads without additional planning time. FULL INVESTIGATION: The Exit. Teachers Leave. Students Suffer. District after district making the switch cited teacher retention as a big advantage of the schedule change. Alto ISD, south of Tyler, said the four-day week offered a "competitive advantage in hiring high-quality faculty and staff." A presentation from New Waverly ISD, north of Houston said, "We believe that the implementation of a four-day instructional week may offer NWISD a pathway to retain and attract high-quality instructors." And in La Vernia ISD, just east of San Antonio, a survey of staff found 82% were interested in a four-day week, with one teacher saying they would probably use the Fridays off for grading and planning. All three districts approved changes to their schedules in February 2023, with three-year pilot programs set to begin in the 2023-24 school year. A February 2023 report by the Teacher Vacancy Task Force highlighted the need to "demonstrate respect and value for teacher time." The report, by the Texas Education Agency, said teachers are responsible for so much more than just teaching, from finding and making copies of instructional materials to completing paperwork and attending meetings and professional development. MORE: Texas governor’s taskforce takes on teacher shortage crisis in new report Districts have touted the four-day instructional week for providing the fifth day for teachers to complete some of those additional tasks. TEA Commissioner Mike Morath is not sold on the four-day week, though. In a March 1, 2023, hearing of the state's Senate Committee on Education, Morath said the schedule shift is "harmful for student achievement on balance," unless certain conditions are met. Morath said districts would have to shift "very, very thoughtfully." For example, any academic disruptions during the week, such as field trips, athletic competitions, extracurriculars and other reasons for students being pulled out of class, should be moved to the non-class day. The "educational experience" on the four class days would then have to be thoughtfully organized to maximize instructional time. On the fifth day, teachers would have "built-in reflection time" and training or professional development time. "There is a subset of districts that when they make those sets of shifts, it does not reduce student achievement," Morath said. "I still don't have any data that shows it increases student achievement, but if all those conditions are true, it is not openly harmful to student achievement. But if all of those conditions are not true, the data is pretty clear. It just reduces student achievement." Many districts are hoping a shorter school week will improve attendance, and in turn, improve achievement. A presentation by China Spring ISD, just outside Waco, said attendance in the district was about 1.5 percentage points lower than before the pandemic. The district approved a four-day week in March 2023. "If the four-day week improves student attendance just to pre-COVID rates, it will increase funding by a little over $300,000," the presentation said. Funding for school districts in Texas is directly tied to student attendance. "When students improve their attendance rates, they improve their academic performance."