Adding 45 minutes to the school day is a great idea if you know what to do with the added time. Japan and other countries who outscore the United States on standardized tests do have longer school days and longer school years. However, research shows that students are doing better in those countries not simply because of increased instruction time. The real benefit to those students comes from increased teacher preparation time.
The United States is at the bottom of the list in time allotted to lesson preparation and evaluation of student work. Indeed, preparation time in other countries can be as much as two to four hours per hour of classroom instruction. In our country, elementary teachers get only about five minutes of preparation time per hour of instruction. Our high school teachers get about five minutes per pupil.
American teachers are the most productive on earth. They do more, with more students, in the least amount of time. If we were to increase instruction time without building more preparation hours into the school day, we would weaken the system.