Question: what is the difference between rug iii and rug iv?
Answer: RUGs IV consists of 66 groups divided into 16 categories (two were added) versus 53 under RUGs III. ... In other words, the historical distribution of total payments to SNFs, based on 2007 claims data applied to RUGs IV, creates the same level of total PPS expenditure for SNFs as would occur under RUGs III.