The 2014 OIG Work Plan includes the following: 

Policies and Practices. We will determine the impact of subordinate facilities in hospitals billing Medicare as being hospital based (provider based) and the extent to which such facilities meet CMS’s criteria. Context—Provider-based status allows a subordinate facility to bill as part of the main provider. Provider-based status

The 2009 Medicare Physician Fee Schedule made some changes regarding physician enrollment. The most significant change is the elimination of retroactive billing. Prior to the 2009 changes, Medicare permitted retroactive billing for up to 27 months following the effective date of a physician’s Medicare enrollment, to allow physicians to bill for services that they provided while the