The clusters created by the use of statistical clustering do not match the three rate areas identified in earlier studies or the maximum payment rates that were informed by the 2016 Market Price Study findings. Thus, we analyzed the 2018 price data by three rate areas as was done in the past (a similar strategy was used for the 2014 and 2016 studies). As noted below, the analyses further documented that provider changes in pricing practices made the three rate areas no longer a valid representation of market prices. But analyzing data by the three rate areas allowed us to compare 2018 market prices with maximum payment rates currently used by the Oregon Department of Human Services (DHS). This supplemental document was produced for DHS's use in making the transition from geographically grouping prices based on the previous three rate areas (A, B, C) to grouping prices in the clusters that appear to better represent the current market. Specifically, this supplemental presents the 2018 findings using the same three rate areas for all three types of care to geographically group prices by zip code. (author abstract)