Submitted on July 14, 2010

The following quote comes from the Obama Administration’s education "blueprint," which is its plan for reauthorizing ESEA, placing a heavy emphasis, among many other things, on overhauling teacher human capital policies:

Of all the work that occurs at every level of our education system, the interaction between teacher and student is the primary determinant of student success.

Specific wordings vary, but if you follow education even casually, you hear some version of this argument with incredible frequency. In fact, most Americans are hearing it – I’d be surprised if many days pass when some approximation of it isn’t made in a newspaper, magazine, or high-traffic blog. It is the shorthand justification – the talking point, if you will – for the current efforts to base teachers’ hiring, firing, evaluation, and compensation on students’ test scores and other "performance” measures.

Now, anyone outside of the education research/policy arena who reads the sentence above might very well walk away thinking that teachers are the silver bullet, more important than everything else, perhaps everything else combined. I cannot prove it, but I suspect that many Americans actually believe that. It is false.

As is so often the case with this argument, the sentence is carefully worded with the qualifier "at every level of our education system” so as to be essentially in line with the research. This is critical because it signals (very poorly in this case) that teachers are the most influential schooling factor in student achievement (which the blueprint calls "success”). And, indeed, this is the current empirical consensus. It means teachers have a larger effect (far larger, actually) than principals, facilities, textbooks, class size, technology, and all other school-related factors than can be measured.

But in the big picture, roughly 60 percent of achievement outcomes is explained by student and family background characteristics (most are unobserved, but likely pertain to income/poverty). Observable and unobservable schooling factors explain roughly 20 percent, most of this (10-15 percent) being teacher effects. The rest of the variation (about 20 percent) is unexplained (error). In other words, though precise estimates vary, the preponderance of evidence shows that achievement differences between students are overwhelmingly attributable to factors outside of schools and classrooms (see Hanushek et al. 1998; Rockoff 2003; Goldhaber et al. 1999; Rowan et al. 2002; Nye et al. 2004).

Now, to be clear: this does not mean that teachers aren’t really important, nor that increasing teacher quality can only generate tiny improvements. The holder of the title of Most Influential Schooling Factor, even in the big causal picture, exerts substantial influence. More practically, school-related factors are the only ones that education policy can directly address.

So, teachers matter, and there are effective and less effective ones. And less effective ones can be made better, which would improve student performance. I dare say that teachers would agree completely.

Yet anyone reading or hearing the endless repetition of the standard teacher impact argument may very well think that teachers are all that matters. They might not spot, in the case of the blueprint’s version, the twist of phrase ("at every level of our education system”) that limits the scope to schooling factors. And even if they do, they may not be aware of how much schooling matters compared with non-school factors.

As a result, they may also be more likely to unfairly blame teachers for the huge proportion of variation that is "out of their hands," instead of the extremely important factors, like poverty and early childhood development, which we need to address at the same time. These people will also have unreasonable expectations for teacher quality policies. They’ll expect immediate, miraculous progress, when real improvements are gradual and sustained.

So, in my humble view, those who make the teacher effects argument to non-technical audiences should consider making it more clearly. Admittedly, the blueprint’s wording is unusually fuzzy. More commonly, the argument will use the phrase "schooling factor” or something similar. This is much clearer, and it is not misleading per se, but it is still probably insufficient for many people to get the distinction (a disturbing proportion of people making the argument don’t give any qualifier at all).

One easy way to achieve such clarity would be to consistently offer a few quick words explaining that we are not talking about students’ background or other factors outside of schools’ control. This could largely eliminate any misunderstandings, while still getting an important point across. And that’s what good teaching is all about, right?