Recently, three economists—Oded Netzer and Alain Lemaire, both of Columbia, and Michal Herzenstein of the University of Delaware—looked for ways to predict the likelihood of whether a borrower would pay back a loan. The scholars used data from Prosper, a peer-to-peer lending site. Potential borrowers write a brief description of why they need a loan and why they are likely to make good on it, and potential lenders decide whether to provide them the money. Overall, about 13 percent of borrowers defaulted on their loan.