Figure 4-2 Mistake-Proofing the Design of Health Care Processes - Figure 4.2. Fault tree showing the effect of less reliable mistake-proofing device Figure 4.3. Fault tree showing reliability of a mistake-proofing device Return to Document Current as of May 2007 Internet Citation: Figure 4-2: Mistake-Proofing the Design of Health Care Processes -. May 2007. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/professionals/quality-patient-safety/patient-safety-resources/resources/mistakeproof/mistakefig4-2.html