At the bottom of the study you see education is the most important factor in career success for your first job. About 7x more accurate than parent's income.
To elaborate: if, hypothetically, one's parent's income was a huge determining factor in one's education, and in turn one's education was the only relevant factor to one's income, then there would be a 100% correlation between one's education and one's income, and a statistically much smaller one between one's parent's income and one's education.
Although we see that strong correlation between education and income, we should evaluate the previous step through analyzing the correlation of parent's income to your education, not the correlation of parent's income to your income as that would be more indirect.
Please correct me if I'm missing something.
> One of the really striking findings of the study was, that you would in some sense really rather know where somebody went to college rather than how much money their parents make, if you wanted to guess how much money they were going to make in the future