Statistically speaking, tracking tended to diminish learning and boost inequality wherever it was tried. In general, the younger tracking happened, the worse the entire country did on PISA. There seemed to be some kind of ghetto effect: once kids were labeled and segregated into the lower track, their learning slowed down.
We have to go from what is essentially an industrial model of education, a manufacturing model, which is based on linearity and conformity and batching people. We have to move to a model that is based more on principles of agriculture. We have to recognize that human flourishing is not a mechanical process; it's an organic process. And you cannot predict the outcome of human development. All you can do, like a farmer, is create the conditions under which they will begin to flourish.