Improvement in ADE rate did not occur at either hospital with any one particular intervention, or even after several conventional interventions had time to take effect. Instead, instituting many simultaneous system changes, proactively assessing risk, and expanding the scope of intervention were each essential to sustaining the described reductions in harm. The next step toward eliminating ADEs requires simultaneous communication across systems in a way that is manageable, approachable, and adaptable, and that supports the elements of change. A system of mutually informed processes--from medication selection and entry through preparation and dispensing, administration, monitoring, and reconciliation--should result in safe, patient-centered, reliable, and efficient medication use. In March 2007, Ascension Health, drawing on the work described in this article, began developing such a system.