A note for Massachusetts on "pay for performance" from Baltimore

If you've been listening to Secretary Peyser, you may have noticed that he keeps bringing up this:
moving to "paying for performance"
That's from my notes on his speech to MASBO, 'though he gave the same speech to Mass Inc, as well, it appears.
Interesting note: it appears that the city of Baltimore has, at least in part, used a pay for performance model since 2009 in funding their schools. If you skim down here, in Bruce Baker's analysis of Baltimore's funding model, you can find it under "Baltimore's Big Fat Weighted Student Funding Fail." Baker did more of an analysis when Baltimore first proposed the model (back in 2009), and then he says this: 

...a likely outcome of the report’s recommendation for rewarding schools serving high performers and children identified as gifted, and for eliminating poverty weighting, will be the advent of more regressive within-district resource allocation formulas than have been seen to date.

(that's from page 5)

Essentially what any such formula does is flip the very foundation of the foundation formula on its head. Rather than recognizing that students with greater need require greater resources--the principle on which the foundation formula rests--it instead advantages those who are doing well. I have heard the Secretary reference "growth" in some of these speeches; note that there is still a correlation between growth and income, 'though it varies somewhat with what sort of growth model one uses.

This also continues the fallacy that funding is some sort of a reward: that if you do well, you get rewarded with more money, but if you do poorly, you get money taken away.
It is abundantly clear in Massachusetts, however, that this is Constitutionally not the case: funding is simply a Constitutional mandate.