As noted in the RAC SOW:
The RAC shall not attempt to identify any overpayment or underpayment more than 3 years past the date of the initial determination made on the claim. The initial determination date is defines ad the claim paid date.
October 1, 2007 is the magic date, meaning, right now, RACs can only go back this far. As of the writing of this post, that is about 2.5 years of lookback.
Once we reach October 1, 2010, lookback will be a moving 3 year window.
This is simply the time window in which a RAC can look, it is the furthest date in the past the RAC can review files.
So, if you have “bad files” beyond the lookback date, you are safe.
Until we reach October 1, 2010, you actually have a “bargain” review window, as the window is less than 3 years.