A recent government audit is raising new questions about whether agencies should rely on contractors to check the backgrounds of people applying for federal jobs or credentials. The Transportation Worker Identification Credential (TWIC) is a gold pass into secure areas of the nation’s ports, railways and other transportation infrastructure. The TSA’s Adjudication Center screens people who apply for the cards. Jenny Grover, acting director for homeland security and justice issues at the Government Accountability Office, explains her concerns with the center.