Obviously, you don't need any achievement data, other than profits. Look at any other commodity or service and you don't need to be asking yourself if X or Y is better. Look at the profits and you will easily see which one is currently better. Your question is much more philosophical than empirical. Who is better able to judge whether a particular product is better? Public school teachers would just love to tell you that the best product is public education, but that's because they don't want competition. We can easily discount their opinions because of obvious bias. The more bias they have, the more obvious they fear competition. If you dislike looking at this from a free market perspective, then I'm sure the math boffins could come up with an algebraic equation that looks at the money a community spends to educate their children vs. the time that takes to receive that education minus whatever they could receive if they were to forgo a formal education in favor of entering straight into a trade from an early age. Set a cut-off age of say 40 and then calculate the results. Or you could simply look at how mandating a formal education in a particular area has helped raise the GDP of that area, minus the cost of any social welfare services.