Externalities of college education

I am currently studying externalities in my economics course at Hagerstown Community College. My experience at Gettysburg College along with my current struggle with student loan debt prompted a short investigation into the positive and negative externalities associated with higher education. 
Higher education holds a lot of benefits for those enrolled in degree programs. Over all, individuals with a college degree will be able to make more money over the course of their lifetime. In addition, a college degree opens doors for professional advancement, which in turn improves your social status. There is an element to higher education however that creates negative externalities for the country as a whole. The federal government began providing students loans in 1958 through the national Defense Education Act. Many student loans through the federal government are subsidized such that the government pays any interest on the loan before repayment begins. By creating a loan program that makes access to higher education more easily attainable, the federal government is able to bring in revenue from interests on loans. In 2013 in was reported that student loan debt through the federal government had surpassed the 1 trillion dollar mark. This is a huge negative externality associated with higher education. The government has taken on the burden of student loan debt. With loan forgiveness programs such as forgiveness for teachers and medical professionals, as well as a cap on how long individuals must pay back on their loans, a part of the 1 trillion dollar debt will never be paid back and thus the potential revenue decreases.
On the opposite side of the issue, college educated individuals create a positive externality for society as a whole. These individuals will be more likely to pay taxes (as a result of higher income). Further more, it is found that a college education makes individuals more engaged in politics, creating a more informed group of voters. Finally, the recent for push for STEM (science, technology, engineering, mathematics) related studies will provide the nation with an innovative work force that will aid in the foreword progress of this country.