The Washington Post, December 5, 2013
Every week, usually on Tuesday, the Centers for Medicare & Medicaid Services sends state Medicaid departments something called a "flat file." These files are sort of similar to the much-discussed 834 transmissions, which the exchange sends to an insurance plan when someone signs up. Except the flat files are for the Medicaid program, and lists people that the exchange thinks -- but hasn't officially determined -- will be eligible for the Medicaid program. And, much like the those 834 transmissions, Medicaid officials say, these flat files are riddled with errors and incomplete information.