The Colorado School Finance Project reports that 80 of Colorado's 178 districts, or 45 percent, have all their schools on four-day weeks. Nine more districts have some schools on four-day weeks, meaning half of all the districts in the state have at least some students on this schedule. Here's how that maps out:

Sterling's RE-1 Valley School District, on the northeastern Plains, is about a month into its first school year with a four-day schedule. Superintendent Jan DeLay tells Colorado Matters she expects the district will save about $900,000 this year wth the changes, mostly by turning paraprofessionals, janitors, and other employees into part time workers who then won't be eligible for benefits, including health insurance.

What does all this mean for the quality of education? A recent state report found academic performance is not negatively affected by the change, reflecting findings from a study published in the MIT journal Education Finance and Policy last year, which drew on Colorado data. However, the Colorado Department of Education did not break out performance measures for higher needs students, and did not address how the change may affect the achievement gap between white and minority students, which is particularly high in Colorado.