The Net Present Value test is a complex computer model used by loan servicers to determine whether a homeowner qualifies for the federal loan modification program. The test compares two scenarios – modification and foreclosure – and determines which would be more profitable for the lender. If it’s foreclosure, the lender has no obligation to modify the loan. But the model is a black box. What goes in isn’t entirely clear, and what comes out isn’t always reliable.
http://www.fdic.gov/consumers/loans/loanmod/FDICLoanMod.pdf