"True" in this context wouldn't mean anything more to me than a significant positive correlation. How do you know there is a positive correlation? I can think

"True" in this context wouldn't mean anything more to me than a significant positive correlation. How do you know there is a positive correlation? I can think of several reasons why there wouldn't be. In particular, a college graduate will tend to be unsatisfied with a job for which he or she is overqualified, leading to a drop in morale and an increase in turnover.