The critique is not that it's impossible for all changes to measure improvement, just that it isn't possible in many cases, because the ideas about what constit

The critique is not that it's impossible for all changes to measure improvement, just that it isn't possible in many cases, because the ideas about what constitutes improvement differ. And even if there was agreement on a set of aspects, measuring them is not the holy grail. You can rarely measure the effect directly. You have to measure some proxy (operationalize it). And the definition of that proxy is going to cause problems. That, plus --of course-- vested interests, makes that you can't fix everything. The best you can hope for is gradual improvement, and a change of direction when the plan doesn't work out as hoped. Those are political choices, not technical.