I&#x27;m not disagreeing with you per sé, but it is possible that some crucial stuff is learned in the 15 years before these tests were administered?<p>The reason I&#x27;m asking is that purely based on a &#x27;hunch&#x27;, I feel that the most useful years of my education were before the age of around 12-13 and after the age of 20. I have no solid evidence to support this, just my experience and that of my peers.<p>Edit: to try and support my hunch: in my country 12-13 is the age where the &#x27;sorting hat&#x27; is applied and you move to middle&#x2F;high school (physically different location, on of three levels based on earlier performance), and 20 is generally around the second or third year of &#x27;higher vocational training&#x27; or &#x27;university&#x27; where the non-motivated are sorted out and (generally) the ones who are going to finish college are left. It&#x27;s also the point where classes become less general, multiple-choice, massive (300+ classes sometimes) and instead become more focused and interesting.