Flawed Comparison from OECD
The OECD has a report, Education at a Glance 2010, that provides a shockingly flawed comparison of the amount of time U.S. teachers work relative to teachers in other countries. According to the report, U.S. teachers work 1,913 hours over a 180 day school year that is 36 weeks long. And also according to the report, the average OECD teacher only works 1,659 hours over a school year of 187 days that is 38 weeks long.
So, if we believe these OECD numbers (which the WSJ apparently did in this blog post), U.S. teachers work 15.3% more hours per year than do their colleagues in other developed countries.
But if you believe the OECD comparison I have a lovely bridge to sell to you. According to the report’s methodological appendix, the method by which the U.S. information was collected was different (and clearly less reliable) than how it was collected from all of the other countries. In every country except the U.S. the hours worked was derived from teacher contracts or laws. But in the U.S. the information was drawn from self-reported responses to a survey of teachers. (See p. 75 of the appendix).
A valid comparison would require that the information be collected in similar ways across all countries — either we rely upon self-reports in surveys of teachers for all countries or we rely on contractual hours for everyone. But using self-reports for the U.S. and contractual hours for everyone else produces obvious distortions. People may be inclined to exaggerate the hours they work in a survey. And the definition of time worked is ambiguous. If I think about my students while I am brushing my teeth or running on the treadmill am I working during that time?
We have good reason to suspect that the self-reports from U.S. teachers are over-stated. If teachers really worked 1,913 hours over 180 days, as the report claims, they would be working 10.63 hours per day. And the numbers I’ve provided are just for primary school students. For high schools, the OECD report claims U.S. teachers are working 1,998 hours over 180 days, which works out to 11.1 hours per day. I know some teachers are very conscientious and work long hours but I simply do not believe that the average high school teacher is working 11.1 hours per day.
I know this might invite the wrath of Diane Ravitch’s Army of Angry Teachers, but I suspect that the average hours worked by U.S. teachers is significantly less than the OECD says (and the WSJ repeats). And I know that the comparison between U.S. and other countries is flawed by collecting the information from self-reports in the U.S. but from contracts everywhere else.
-Jay P. Greene