The OIG performed a statistical review of SNF part A bills for 2006 and 2008.  They noted a significant increase in the number of claims for the highest level of Rehab combined with the greatest level of ADL impairment.

Here is a link to a summary of the report - http://www.racmonitor.com/news/33-top-stories/489-questionable-skilled-nursing-billings-could-top-500-million.html
Here is the link to the report itself - http://www.oig.hhs.gov/oei/reports/oei-02-09-00202.pdf

It is worth scanning the report to see the significant difference in Therapy needs based on the ownership of the building.

• For Profit Chains have significantly higher therapy levels than do nonprofits and publically owned nursing facilities.

• The investigators don’t consider that therapy is an expensive service and that perhaps only the more aggressive facilities can afford to staff at levels capable of delivering 1-2 hours a day of therapy.

The OIG is planning to issue a follow-up report where the set of high therapy claims is subjected to medical review to see how many should have been denied based on audit findings.  You can be certain that they will discover a high error rate.  This will lead to new efforts to require more detailed documentation of need in the medical record.