system
Given the following post, respond as if you're commenting on Reddit:
human
How do the "return on investment" figures for going to college account for the fact that the type of person who gets a degree from college is also the type of person who was going to make more money than average even if they hadn't gone to college?
gpt
Some analyses look at people just above and just below an admissions cutoff to see what the returns on college look like for people who are similar across many observable characteristics. For example, you may look at a state where most students go to the big local state university, and they automatically admit students above a certain threshold, say GPA or SAT score. By comparing students right around that threshold that significantly alters likelihood of college enrollment and controlling for other observable characteristics like parents' education level and income, you can tease out a sense of the returns of the college degree. Research design around thresholds (fuzzy or strict) are popular mechanisms for trying to compare as similar of people, but of course any method you use is always subject to bias from omitted variables that you cannot measure or quantify like personality.