You have a new CFO who would like to familiarize herself with the facility quickly. She asked finance to run her a case mix index from October 2005 to September 2015 in order to observe how the facility has been doing overall. She has noticed some anomalies in the data and has asked you to explain how your coders have been performing on audit and whether there are problems she needs to address in this regard. Your coders have been performing well on random audit as well as external review, so you turn her attention to the case mix index data. What problems might there be with the data and how can it be re-run in a meaningful way?