An individual parent doesn't figure this out on their own. The market, composed of all parents, determines it. The market has access to more information than an

An individual parent doesn't figure this out on their own. The market, composed of all parents, determines it. The market has access to more information than any phd will ever be privy, because it knows the individual feelings of every parent, child, teacher, and administrator. The market is unique in being able to perform randomized, controlled, double-blinded studies on the whole population, whereas phds are stuck looking at correlational data of small samples. The market performs continuous replication of every result ever identified, such that subgroups can be made arbitrarily small while maintaining significant p-values (and has no publication bias). And the market has access to the intellect of every phd, bachelors degree, or idiot that read a book once who ever had children or who wants to make a quick buck, conspiring in the greatest peer-review in history.