I. Introduction
Making higher education affordable has a significant impact on ensuring the nation's economic prosperity and represents a central focus of the government when making education policies [1] . Yet student loan debt in the United States has blown past the trillion-dollar mark, exceeding Americans’ combined credit card and auto loan debts [2]. As the cost in college education (tuitions, fees and living expenses) has skyrocketed over the past few decades, prolonged graduation time has become a crucial contributing factor to the ever-growing student loan debt. In fact, recent studies show that only 50 of the more than 580 public four-year institutions in the United States have on-time graduation rates at or above 50 percent for their full-time students [2].