Probably like with many things, there is a U-curve involved. The main thing about planned activities is that if they're chosen well, they're beneficial, if cho

Probably like with many things, there is a U-curve involved. The main thing about planned activities is that if they're chosen well, they're beneficial, if chosen poorly they're a waste of time. There needs to be more detail. Also some parents misinterpreted the idea and do things instead of their kids not for them - e.g. fake homework instead of working through it with the kid to let them learn. Trying to push into better schools and universities is another thing that correlates with success, academic or otherwise. But probably it is also problematic if you overdo it. It would be interesting to stratify by 10% and look for interesting and meaningful differences in detail. For instance, there might be just right degree of child freedom involved. Ask parents about number of hours of unstructured play and what it is in rough categories. Check if parents do "play dates" or not. (Such categories may be media use, video or board games, unstructured sports, free roaming, visits with friends, hobbies. Ask how much activity time is social and with how many others.)