College admissions officers trumpet graduates' success in finding well-paying jobs. But the schools often have a hard time getting solid proof. Boiling down employment outcomes to a single metric isn't easy, many college officials say, since hurdles stand in the way of gathering meaningful figures and conveying them. Others say they are leery of tying the nuances of educational success to dollar figures. But with student-loan debt outstanding hitting a record $1.1 trillion, according to the Federal Reserve Bank of New York, the issue of quantifying graduate success has become increasingly important as colleges come under pressure to prove the education they provide is worth the investment.