I think part of the problem is that it's a very difficult question to quantify - we can't control the inputs, we're not totally sure what we want from the outputs, it's unlikely that a uniform process will work to get the outputs we want, and we don't have the materials to guarantee a uniform process from start to finish.

On the input side, each incoming class is different: they vary across geographic and socioeconomic lines, they're all affected by factors which occurred years before we ever got them in a classroom to begin with.

On the output side, we really _Don't_ know what we want. It's easy to say, "students who can read, write, and do math," but the devil, as always, is in the details - how do we measure that in a way that doesn't immediately become a metrics problem á la No Child Left Behind?. More than anything, we need to foster successful individuals - but we're not sure how to do that on a large scale and the education system is but one part of a child's life.

The answer in a lot of ways seems to be "Very Good Teachers" - but what makes a good teacher? What sort of support structure is required? Are we willing to pay for enough Very Good Teachers? Do we have enough? Can we train more?

Further, to what degree does the attempt to constrain the education system so we can quantify the results inhibit individuality? In assuring a child knows his multiplication tables, are we imposing a system that will prevent that child from the free expression that would eventually lead to a great artist? Many of our finest works - the pieces of art by which we define our culture, spring from people who would, by any other metric, be considered failures by a system intended to raise successful individuals.

All this is complicated by the fact that the end result of a good education system ultimately is a good society - something we won't know until 20, 30, 40 years later. Everything else is a proxy: We think a high college attendance or graduation rate will get us there, we think more scientists and engineers will get us there, we think more well-rounded individuals will get us there, but ultimately, we don't know what makes a good society, nor what works to get us there.

I think there are improvements we can make, teaching methods that work better than others, and probably ways to quantify some of those differences, but ultimately, we don't even know the bounds of the problem we're trying to solve in education.

Great comment. I think the difficulty in defining what makes a good teacher is as difficult as what defines a good parent. In rough terms, I think a good parent means someone who raises a compassionate, honest child.

Similarly, a good teacher / education system is one that raises inquisitive students. I've long believed it's better to graduate kids who love algebra vs. those that know and hate calculus. Because in 10 years, the ones who loved algebra will probably end up loving calculus too (instead of developing a lifelong aversion to math, and learning in general).

So, my meta-reply would be to search for a system that tries to generate genuine interest in learning. (Plug: I try to blog in this manner at http://betterexplained.com).

In my high school we were all given laptops and all the teachers had SmartBoards. Here's how the technology was used:

1. We all gamed in class and got a shred of work done.

2. A fraction of the teachers used the boards, even though they were all trained how to.

3. They were crappy Dells that spent a good deal of time being repaired so many students were without a laptop on any given day.

4. I was personally taken home in a police car by the school officer and had my laptop confiscated for using VNC on a teacher's unsecured Smartboard. Those things caused way more trouble than good.

Oh...and our rival school all bombarded the local Blackboard servers on Exam day and DDoS'ed their way out of exams.

That's because the goals of teaching are bizarrely ill-defined. With drug laws, we have a concrete, measurable outcome we're looking at. Most attempts to actually define a goal for teaching (e.g. with standardized tests) have been derided as measuring the wrong things and harming education in the process by forcing teachers to "teach to the test".

Exactly.

Current efforts at educator performance are attempts to apply basic economics to a real-world complex multivariate issue - how does a given teacher affect the arc of a child's overall education, when decoupled from the child's home environment and overall societal trends?

Accurately measuring this kind of impact would be more similar to modeling weather than say, worker performance. A more accurate model would be like lifetime patient medical outcomes (which we also are poor at measuring in detail)... if we could measure how good a doctor is by the healthfulness of their patients, then we have the basic model by which we can measure educators.

Spot-on. It's incredibly difficult to measure intelligence, and learning could be defined as the delta of intelligence on a particular subject. The best way I can think of would be real-world application of the knowledge (in the form of applied projects), but that gets to be too time consuming and expensive in a world where "education" is mandatory to the point of being a commodity.

Of course, quite a lot is known about what makes a good teacher. It just isn't widely known, let alone taught to new teachers, let alone to current teachers.

See http://www.nytimes.com/2010/03/07/magazine/07Teachers-t.html... and the book that came out of the research featured in the article: "Teach Like a Champion".