Six years after the Deepwater Horizon drilling rig explosion, the Interior Department agencies responsible for overseeing the oil and gas industry have made progress of their own. They've taken several measures to make sure they can hire and retain the people they need to carry out the oversight function. But Interior still has trouble knowing for sure whether the measures are effective. Frank Rusco, director of Natural Resources and Environment Issues at the Government Accountability Office, shares the details on Federal Drive with Tom Temin.