Last week, former Secretary of Education and US Senator Lamar Alexander wrote in the Wall Street Journal that a college degree is both affordable and an excellent investment. He repeated the usual talking point about how a college degree increases lifetime earnings by a million dollars, "on average." That part about averages is perhaps the most important part, since all college degrees are certainly not created equal. In fact, once we start to look at the details, we find that a degree may not be the great deal many higher-education boosters seem to think it is.

In my home state of Minnesota, for example, the cost of obtaining a four-year degree at the University of Minnesota for a resident of Minnesota, North Dakota, South Dakota, Manitoba, or Wisconsin is $100,720 (including room and board and miscellaneous fees). For private schools in Minnesota such as St. Olaf, however, the situation is even worse. A four-year degree at this institution will cost $210,920.

This cost compares to an average starting salary for 2014 college graduates of $48,707. However, like GDP numbers this number is misleading because it is an average of all individuals who obtained a four-year degree in any academic field. Regarding the average student loan debt of an individual who graduated in 2013, about 70 percent of these graduates left college with an average student loan debt of $28,400. This entails the average student starting to pay back these loans six months after graduation or upon leaving school without a degree. The reality of this situation is that assuming a student loan interest rate of 6.8 percent and a ten-year repayment period, the average student will be paying $326.83 every month for 120 months or a cumulative total re-payment of $39,219.28. Depending upon a student's job, this amount can be a substantial monthly financial burden for the average graduate.