Kathleen Porter-Magee is half right, maybe two thirds. Principals should indeed be responsible for evaluating the teachers in their schools—and should have the authority to engage, retain, deploy, and dismiss individual instructors (and other school staff) according to their best judgment.
That does not, however, mean "education reformers [should] get out of the business of trying to improve the civil service rules of our broken education bureaucracies...." Surely she doesn't want the system's present HR rules and practices to endure intact. And surely they're not going to be wiped away altogether. So they need to be reformulated. And one crucial area of reform (among many) does involve teacher evaluations and the appropriate use of student achievement information—test scores and more—within such evaluations.
No, teacher evaluations should not be based entirely on student test scores. No, I don't think such evaluations should be made public (though significant portions of them should be accessible to parents, especially the parts linked to student achievement within teachers' classrooms). But chaos will reign if there are no district or statewide practices, templates, model programs, and suchlike for teacher evaluations. Though I can picture an education system consisting entirely of charter-like schools, each with the freedom to determine its own evaluation system—more or less what I believe Kathleen has in mind—I cannot picture a traditional district where neighboring schools follow radically different protocols for evaluating their teachers. Imagine, say, having student value-added scores count for 35 percent of a 5th grade teacher's evaluation at the Jefferson School but for 65 percent for a comparable teacher at the nearby Lincoln School. It just won't work and it just won't happen.
I respectfully suggest that my friend Kathleen rethink that one-third (or maybe half) of her approach.