Is shorter calendar shortchanging Michigan students?

From The Detroit News: An analysis of Michigan Department of Education data shows that three out of four of the state's school districts educate children fewer than 180 days a year. That was the minimum required by state law until lawmakers eliminated the mandate six years ago. Cash-strapped districts are shrinking the calendar to save money, a choice that makes short-term economic sense. But the state's top education official says the shorter calendars may be hurting the education of Michigan's children.