According to a report from the U.S. Census Bureau, "the average [lifetime] earnings of a full-time, year round worker with a high school education are about $1.2 million compared with $2.1 million for a college graduate." This indicates that there is a considerable benefit to a graduate from investing in his or her own education. Tuition at most state universities cover only about two-thirds to three-quarters of the cost, so the state applies a Pigouvian subsidy to college education.
If a Pigouvian subsidy is appropriate, is the externality created by a college education a positive or a negative externality? What does this imply about the differences between the costs and benefits to students compared to social costs and benefits? What are some reasons for the differences?