In very narrow areas. For example, there are training programs that look at your answers to questions and take you to a more or less difficult section, or possibly back to the beginning with a simpler explanation.

Examples of this are the training programs for SAT/GRE. (Also the tests themselves are like this.)

I know the national guard is doing stuff in this area. It seems clear enough that the NEA and other teacher orgs are vehemently opposed to a lot of this stuff. They've funded studies, for example, that show that distance education has very limited utility. Of course this is all very clinical and they started their "studies" with open minds, and it's simple coincidence that they've produced the results their leadership expected.

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