A national scholar is taking a fresh look at an old misperception about four-day schools: the notion that a shorter school week is a big money-saver.

Paul Hill, a research professor at the University of Washington at Bothell, used the Newcastle, Okla., school district as a case study to look at four-day school budgets. The switch to a four-day calendar cut about $110,000 out of a $12 million budget, a savings of 0.9 percent.

“There are lots of ways to save 1 percent of the budget, none pain-free,” Hill wrote in a column in Education Week Friday.

However, he wrote, districts have other options. Based on normal turnover, a district such as Newcastle could see four to six of its 100 teachers leave in a year. Allowing those positions to go dark would trim 1 percent of the budget.

If the cost-saving conundrum sounds familiar, it should. In an in-depth series on four-day schools in November 2015, Idaho Education News determined that districts save little money by switching to fewer (and longer) school days. These savings have been modest not just in Idaho, but across the country.

But as Hill notes in his column, communities often stick with a four-day calendar for reasons that have little to do with budgets. The four-day calendar and three-day weekends often become popular with parents, making it politically difficult to switch back.

“Governors and state superintendents of education need to make sure local communities look at real numbers and don’t jump blindly onto a bandwagon that they might never be able to get off,” Hill wrote.

In 2016-17, 44 Idaho school districts and 11 charter schools operated on a four-day calendar. The Kamiah School District in north-central Idaho is considering a shift to a four-day schedule.

More reading: A closer look at our November 2015 series on four-day schools.