Private colleges with the biggest payoff

20-year return on investment: $946,500
Annualized return: 12.8%
Total 4-year cost of attendance : $230,200

Babson College is known for producing captains of industry and entrepreneurs.

This business degree-only school employs unique teaching strategies that seem to be paying off for its grads. According to the school, 99% of graduates have jobs or go on to graduate school within six months.

One particular area of study the school is known for is entrepreneurship.

Related: Most expensive colleges

"Entrepreneurship as an area of study has really started to grow across colleges," said PayScale's Frank. "If graduates are having success there, you could see how that would result in good earnings potential down the road."

Around 7% of Babson graduates start their own businesses, and many go into finance and marketing. According to PayScale, early career salaries are around $61,000 -- high enough for the business school to compete with the STEM schools that dominate the list of schools with the best return on investment.

First published March 10, 2015: 1:18 PM ET

Source: PayScale
Based on employee survey data, PayScale calculated total median pay for each private school's undergraduate alumni over a 20-year period and compared it to the median pay for a high school graduate over 24 years. The return on investment (ROI) in 2014 dollars was determined by taking the difference between those median pay figures and subtracting the cost of attending the school in 2014 -- including tuition, room and board, and other costs -- and adjusting for scholarships and grants. The annualized ROI is calculated by dividing the earnings differential by the total cost and represents the percent of expected ROI received each year after graduation. Unlike in previous PayScale reports, the earnings differentials in this report do not take into account graduation rates. Alumni who attended graduate school or other higher education were excluded.

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