Wednesday, September 8, 2010

Be Careful When Calling For "Great Teachers"

Davis Guggenheim, director of the forthcoming documentary "Waiting for Superman," writes an op-ed for the Huffington Post (hat tip: Gotham Schools) that fits pretty well with conventional wisdom on schools nowadays.  In it, he repeatedly asserts that "We can't have great schools without great teachers"

This is true.  We can't.  But this is also a dangerously overly simplified narrative.

I say this for three reasons:

1.) Teachers are the single most important within-school factor, there's really no dispute over this.  But estimates of teacher impact on student test scores find that teacher quality only explains about 20% of the variation in these test scores.  So let's be careful not to insinuate that teachers are the only thing that matter or that teachers should be expected to fix everything.

2.) Lines like the one Guggenheim uses are great soundbites, but too many people assume that teachers are simply "good" or "bad" when they read or hear such things.  In reality, teachers don't come out of the womb either good or bad; they perform poorly or superbly for any number of reasons.  These include, but are not limited to: experience, class size, school quality, curricula, the actions of other teachers, the actions of administrators, and the particular students they've been assigned this year.  All of these factors are mostly out of a teacher's control in any given year.  So simply searching for great teachers isn't really enough: we have to search for them, train them, place them in a context where they can succeed, and then convince them to keep doing what they do (and doing it well).

3.) Guggenheim suggests that the solution to all our problems in education is a simple one: we need great teachers.  He further suggests that curriculum, class size, etc. don't really matter.  Both of these are false.  Finding, training, and retaining great teachers is anything but simple, and teacher quality is but one of many, many things that matter in education.

I can't fault Guggenheim for his obsession with teacher quality.  It's probably the one factor that's both important enough and manipulable enough for policy changes to have an immediate and significant impact.  But if there's one thing that I've learned about our educational system it's that changing one factor should never be expected to solve everything.

I need to add to my list of things people should remember about education policy that education is an enormously complicated process involving innumerate moving parts and, as such, we cannot -- and should not -- expect changing one factor to solve all of the system's problems.  There is no magic bullet, no simple fix; changing the course of one child's education is a lifelong process and changing the course of millions of kids' educations is infinitely more difficult.

Teacher quality seems like a good place to start, but let's recognize both that changing it won't be easy and that it's not a good place to stop


Matt Di Carlo said...

Good post as usual. Sounds like we largely agree:

Though my literature review showed that teacher effects explained more like 10-15 percent of the variation. Not a huge difference, obviously, but can you post a couple of papers that show 20 percent? I'd like to read them.

Corey Bunje Bower said...

I probably should've worded it slightly differently -- something to the effect of "maybe as much as 20% or so". If memory serves, I saw 19% in a value-added analysis by some folks at RAND, but there are smaller estimates as well. But whether it's really 10% or 20%, my point still stands: teachers are really important, but they're far from the only thing that matters.

Parry Graham said...

I agree with your central point -- just saying "we need good teachers" simplifies things in ways that can be misleading or incomplete.

At the same time, as a public school principal, I like the focus on "great teachers" because it creates a comprehensible framework to use when talking about the more complicated stuff. Why do we need effective curricula, reasonable class sizes, strong school leaders, etc., etc.? Because good teachers are so important, and those factors limit or augment the job that good teachers can do.

Both for my staff and for my parents, I find that it helps to have an over-riding narrative of teacher quality (or, even better, teaching quality) that I can use when engaging in more complex discussions about public education.


Nancy Flanagan said...

The argument goes all the way back to Coleman: how much difference can a school make? VAM has made it possible to narrow the unit of measurement down to the teacher--and individual teachers have more impact than other school factors and functions--so that's where we're stuck. The available measurement tools define what we're trying to measure.

In an Ed Leadership class, we also did a lit review on how much impact schooling variables have on student learning (measured, of course, by highly variable and unaligned standardized tests--another shaky tool). The best we could come up with was in the high single digits, with teacher quality having the greatest impact, much more than time in school, curriculum, governance or (to the dismay of many in the class) "leadership."

Teachers also have far greater reach and range than what's currently being measured. The impact of a teacher who instills a disciplinary passion--or confidence--in a child is almost beyond measure.

As a teacher, I would never push too hard against the idea that great teachers make a huge difference--only because the alternative viewpoints (all we need is more charter schools, for example) are far worse.