GEOFF BENNETT: Across the country, more school districts than ever are making the change to a four-day school week.

Our St. Louis community's correspondent, Gabrielle Hays, traveled to one of those districts to see how teachers and parents are adjusting.

GABRIELLE HAYS: In Missouri, nearly a third of the districts have already made the switch.

DALE HERL, Superintendent, Independence, Missouri, School District: This was 100 percent about attracting and retaining the very best staff.

GABRIELLE HAYS: Independent school district superintendent Dale Herl led the change to a four-day school week this year.

DALE HERL: Right from the start, we wanted everyone to know that this was not about saving money.

We know we're actually spending more on this model.

GABRIELLE HAYS: The average starting teacher salary in Missouri is the lowest in the nation, which has caused teachers to leave for better pay or leave the profession altogether.

Almost 14 percent full-time teaching positions were unfilled or filled with underqualified employees in the 2022-2023 school year.

GREGG KLINGINSMITH, superintendent, Warren County, Missouri, School District: We were one of the first rural school districts outside of the St. Louis suburban area.

GABRIELLE HAYS: In the Warren County School District, superintendent Gregg Klinginsmith led the change to a four day school week about five years ago.

GREGG KLINGINSMITH: I really wish this was a story about a school district finding ways to pay teachers the highest salary in the state, but, unfortunately, we just don't have the revenue to pay competitively.

And so we were losing teachers at a pretty high rate.

GABRIELLE HAYS: Aaron Pallas with the Teachers College at Columbia University says this new model is quickly gaining popularity nationwide.

AARON PALLAS, Columbia University: We have seen a sharp increase in the number of school districts around the country that have adopted a four-day school week.

GABRIELLE HAYS: Places like Missouri and Oregon have embraced the four-day school week.

In other states like Oklahoma, the government has limited which districts can make the change, for fear of students falling behind.

AARON PALLAS: There is some evidence suggesting that students do not learn quite as much in a four-day school week as in a five-day school week, in part because the school week is actually a little bit shorter.

Moving from five days to four often results in a slight reduction in the amount of instructional time that students experience.

And instructional time is a really strong predictor of what students learn.

ANGIE JUDY, Parent: So the first thing that came to my mind, of course, being a former teacher, is just the worry on the at-risk students.

GABRIELLE HAYS: Independence parents like Angie Judy are still adjusting to the changes this year.

ANGIE JUDY: It was told to us that it was to retain teachers.

But I really think there's different ways we can take care of teachers than to do this to a lot of people's families.

GABRIELLE HAYS: And while Independence offers childcare for K-8 students on those days off, it costs $30 each week.

ANGIE JUDY: And I have actually had a few friends who've left the district because they're like, well, if I have to pay for a full day, why not just send them to private school?

Because I want my kid in school five days.

DALE HERL: They're going to get into a routine, and you're not going to have the need for the childcare that you thought you were going to.

GABRIELLE HAYS: Pallas says he expects this issue to crop up more as more districts turn to this model.

AARON PALLAS: For many families, the fifth day is a challenge, because they have to provide care for their children who are not being supervised in school.

And that can be a direct cost for parents, either by having to hire childcare coverage or by staying home and supervising children, at the expense of other things they could be doing with that time.

GABRIELLE HAYS: As for whether the shift to four-days has been successful, Herl says it's too early to tell.

But the results they are seeing in Independence so far are promising.

DALE HERL: The number of applicants that we did have for our open positions, it went up by more than four times what we had the previous year.

So I think it -- yes, it's helping on the retention piece.

But then, as far as attracting qualified candidates, without a doubt, we saw a huge increase.

GABRIELLE HAYS: As for the concern over learning loss, Missouri requires that students must have the same number of instructional hours, regardless of how many days they're in school.

And teachers like Jeanna Dildine say the time is made up with slightly longer days, days where teachers themselves are rested and ready to teach.

JEANNA DILDINE, Teacher: I want people to know that, even though it's just four-days, you are getting four quality days.

And as the saying goes, it's quality over quantity.

And we're all very productive, I have noticed.

We don't waste time because we have four days.

And we are getting as much of their education in those four days as we can.

GABRIELLE HAYS: And Warren County Superintendent Gregg Klinginsmith says, the numbers show that students are not declining academically.

GREGG KLINGINSMITH: Reading levels are about the same for kids.

Test scores are -- now, that -- COVID threw a lot of our data off.

But what we're seeing is, we're about where we were before.

So it's not like we're seeing a big drop in student achievement.

We have tried to run two tax levies to try to increase teacher pay.

Both of those have failed.

And so this has really worked out well for us to retain our staff, give a positive working environment, and then have the best teachers in front of our kids.

GABRIELLE HAYS: As schools across the country juggle things like budget constraints and teacher loss, the shift to a four-day school week may be a new reality in years to come.

For the "PBS NewsHour," I'm Gabrielle Hays.