Change public school teacher compensation

Megan McCardle has an interesting description of the effects of current ways of compensating public school teachers--and of her ideas for needed changes.

I know what some of you are thinking: but if the system weren't set up this way, people would just fire old, expensive teachers! But I'm proposing repeal of the entire Faustian bargain where teachers get systemic bumps merely for aging in place: pay younger teachers more, and make the raises less generous, so everyone gets the same pay for doing the same job. (For the first five years, I think there's some argument for teachers working at a discount. But teacher effectiveness seems to plateau after five years*.) The system should neither punish longevity, nor reward it. And if that were true, principals would have no incentive to fire teachers by age group rather than performance.

I like the footnote that explains her statement about a "plateau after five years" too:

* Yes, yes, that's only if you accept standardized tests as some sort of accurate measurement. Sadly, standardized tests are the only way we have to get, erm, a standard measurement, and no one's offered any very compelling alternative causation that would make teacher quality as measured by these tests rise for the first five years--and then stop--for reasons completely uncorrelated with whatever intangible variables the anti-testitarians believe constitute "actual" teaching performance.