Many school reformers believe that raising academic standards will mean keeping kids in school for more hours a day and more days a year. Students in countries we compete with master more challenging curriculums and outscore Americans on tests in most core academic subjects. These countries all have a school year that is a lot longer than the U.S.'s 180-day average. (In Germany, for example, teachers work 225 days; in Japan and Italy, 215; in England, 195; in Canada and Norway, 190.)

The impression the American public has gotten is that the reason it might be good to lengthen the U.S. school day or year is so we could get more work out of teachers: kids in other countries are learning more because their teachers are teaching more.

But that doesn't square with the facts. The reality is that American teachers spend far more time in the classroom than their counterparts in other countries. A new survey by the international Organization for Economic Cooperation and Development (OECD) shows that U.S. teachers pack more than 1,000 hours of classroom instruction into every school year -- hundreds of hours more than teachers in other countries, even though they work more days.

So how is it possible that teachers in other countries can work many more days a year but teach substantially fewer hours? What are they doing instead?

The answer is that they are busy with tasks that in other countries are considered a normal part of the daily responsibilities of a professional teacher ... In the 15-25 hours of their work week that is not spent in class, teachers confer with each other about students' progress and ways to improve their instructional methods; they work with students individually; and they plan their classroom lessons, often together.

In most professions, there are at least two sides to the job. You work with your patients or clients for part of the time, and you spend part of the time with colleagues discussing what went wrong in your work, what's going right, how you did it, and how others have done it or fluffed it. This exchange of experiences, ideas, and problem-solving approaches provides a vital kind of professional development that most professional people take for granted ...

The work life of American teachers is very different. They spend their days in classroom teaching with virtually no time to learn from and confer with other teachers. They work in isolation in their classrooms, and they do their planning, grading, and thinking alone at home.

Teachers in the United States are teaching longer and harder than teachers anywhere else in the world. But school policymakers might take advice from Jack Bowsher, a former top IBM executive who said, "If 20% of the computers in my computer plant were dropping off the assembly line before they reached the end, and the other 80% reached the end but had defects, the last thing I'd advocate is running the line an extra few hours a day or an extra few weeks a year."

Those who say more time is needed for education may be right. The issue, though, is how the time is spent.