At this morning’s House Budget Commitee hearing, Douglas Elmendorf admitted that the Congressional Budget Office is ill-equipped to measure the signature cost-cutting measure in Paul Ryan’s Medicare reform plan–a government exchange designed to introduce competition into senior health insurance market.

“We don’t model the behavior of physicians. We don’t model the access to care or the quality of care,” said Elmendorf, CBO’s director. “That is a gap in our toolkit.”