Cessna first mapped common materials across its BOMs that could be more effectively managed together as combined groups (it refers to these as Centers of Excellence, or COEs, as described in Chapter 3), commonalities that normally would be lost among disparate supply arrangements. By creating arrangements for manufacturing cells with suppliers to produce these items together to maximize the variation smoothing benefits, it was able to slash lead times and prices and promote dramatically more reliable flow, even for some of the most challenging materials.