How predictive is the school performance for the eventual job (and life) performance of an individual?
This is a very important question. The schools are supposed to educate what is actually useful. (But clearly that is not the case in practice.)
This is also a very broad question under perennial discussion.
In my personal experiences on the creative side of computer science (e.g. research and development for the cutting edge of graphics and HCI), there is a weak positive correlation between school and job performance (around 0.2 to 0.3 if I have to be numeric).
Good school performance reflects positive traits such as talent and work ethics, but also negative traits such as conformity, lack of creativity, and risk aversion.
This is why standard statistics, like grades, schools, and rankings, are not enough and sometimes even misleading. We have to look at more practical evidence, such as publications, projects, and recommendations.
This is also why recruiting top students and employees is very challenging. Top schools and companies do have advantages in attracting top talents, but we only get what we look for. Many of the best people I have worked so far had been bypassed by the traditional screening standards. Conversely, I have also seen many weak people in top institutions.
Maybe one day data analysis and machine learning will solve this problem.
Before that, I rely on the good old way of people reading.
