The Matching Michigan program attempted to replicate the success of the Keystone ICU study at preventing central line–associated bloodstream infections in intensive care units (ICUs) in England. However, Matching Michigan was unsuccessful in that infection rates declined at similar rates in both intervention and control units. A counterpart to the landmark study exploring why the Keystone ICU study succeeded, this ethnographic analysis identified external factors (Matching Michigan was perceived as a regulatory, top-down initiative) and internal factors (participating hospitals had widely varying prior experiences with quality improvement projects) that influenced uptake and success of the project at the individual hospital level. Overall, only 1 of the 19 intervention ICUs studied truly transformed their practices and culture toward preventing hospital-acquired infections.