Ironically, some of the same analysts who lament that teachers are treated as “widgets” promote the misdirected policy bromide that teachers have the “same value” no matter where they teach.
I don't think it is "ironic" though, I think it is an intentional rhetorical strategy. Come up with your argument (Each teacher has an objective, measurable level of quality.), anticipate the strongest critique (You can't treat teachers like simple machines, they're an integral part of tremendously complex systems.), then re-frame your argument using what would otherwise be the best language to attack it (We must stop treating teachers like widgets (by assigning them an objective, measurable level of quality)!). Classic Karl Rove, really.