Stafford loans are student loans that the federal government provides to graduate and undergraduate students to fund their education. Stafford loans can be extended up to 30 years. The Congressional Budget Office (CBO) calculates the cost of these loans by discounting the future cash flows from the loan using the interest rate on the 30-year Treasury bond. The risk of default on the 30-year Treasury bond is extremely low. In contrast, over the life of a Stafford loan, on average about 20% of the amount due is never repaid. What do you think are the implications of using the yield on the 30-year bond to calculate the cost of student loans?