However, research consistently shows that student achievement suffers when districts shift to a four-day week and reduce the total number of hours in school—the more common scenario. The average student in a four-day school experiences 85 fewer total instructional hours per school year than their counterparts at five-day schools, and research shows a corresponding decrease in math and reading scores. A recent study of student performance across six states on the Measures of Academic Performance (MAP) assessment found student scores dropped by 3 percent of a standard deviation in math and 7 percent of a standard deviation in reading, on average, with larger effects at non-rural schools.