Admittedly, the students might not immediately appreciate the gift Emanuel has won for them. But a growing body of evidence suggests that more time at task is crucial to improving educational performance.
For elementary-school students, Chicago's school day will increase from five hours and 45 minutes -- the shortest of any major city in the U.S. -- to seven hours. In addition, the school year will be extended from 170 days to 180 days. All told, the amount of time elementary-school kids spend in school will increase by almost 30 percent. Timothy Knowles, the director of the Urban Education Institute at the University of Chicago, says that no other large U.S. city "has added this much time to the school day and year in one fell swoop -- particularly in such economically tough times."
Research suggests a strong payoff from extra instructional time. A new paper by Victor Lavy of Hebrew University of Jerusalem offers compelling evidence. In September 2004, Israel changed the way it funded elementary schools and directed more resources to schools with a higher percentage of students from disadvantaged backgrounds while reducing funding at other schools. The schools that received more funding used most of it to increase instructional time.