As parents send their kids back to school this fall, the OECD, a group of the world’s industrialized nations, is putting out some dubious claims about how American teachers compare to their counterparts in the rest of the OECD.
OECD studies are sometimes just too ambitious. The truth is that large-scale international comparisons are almost inevitably plagued by inconsistent and unreliable data. The most recent example: The OECD’s Education at a Glance 2013 shows American teachers working more hours than teachers in every OECD country except Chile (see table D4.1 in the study). Sounds impressive!
That’s an inconsistency likely to inflate U.S. hours relative to the rest of the world. School districts in the U.S. require teachers to work about 37 hours per week, but teachers in the School and Staffing Survey claim to work a whopping 53 hours per week! This 16-hour difference shows that, regardless of which estimation method is more accurate, cross-country comparisons that mix and match methods cannot be trusted.
What causes such a big difference between statutory hours and self-reports? It’s the work that teachers do outside the classroom — grading papers, developing lesson plans, calling parents, etc. Statutory hours tend to downplay these activities, while self-reports exaggerate them. Accurately measuring work time outside the classroom requires a special time-use survey, in which respondents give detailed, sequential descriptions of their activities on a given day. The Bureau of Labor Statistics has used this approach to show that the teacher workweek in the U.S. is not unusually short or long — it’s roughly 40 hours.