Cause & Effect Diagrams Scott Davis QI Coordinator Tacoma Pierce County Health Department Recorded 6-12-12

Objectives Understand … Purpose of the CED Elements of the CED How to construct a CED

CEDs When would I use this tool? Most often: Late in the analysis phase when you want to develop theories of cause You might also use it … In assessment phase…to i.d. key drivers of an issue Early in analysis phase…to organize stratification In change phase…to consider solution options Any time you consider how multiple factors might contribute to a specific phenomenon

Analysis Tool: Cause & Effect Diagram “Fishbone” Format (Aishikawa)

Effect Statement Examples Outside referrals take more than a week to process. The data input step takes 3 to 5 hours. 34% of request forms are sent back. Why does printing permits take so long?

Analysis Tool: Cause & Effect Diagram Typical Cause Categories Machines Methods (process) Materials Milieu (Environment) Men (people) Measurement OR: Brainstorm causes on Post-It Notes and then group in natural affinities (see affinity diagram)

Analysis Tool: CED High-level Flow Format

Analysis Tool: “Why” Root Diagram Format Cause Category Cause Category Effect Statement As specific and measureable as possible Specific Theory Theory Theory Cause Category

Analysis Tool Centric CED Format Cause Category Theory Cause Category Specific Theory Effect Statement Cause Category Cause Category Cause Category

Analysis Tool: Cause & Effect Diagram Steps Write specific effect statement. (Usually, but not always, more specific than your original problem statement) Determine format Determine cause categories/steps Brainstorm theories of cause for each category Keep asking “why?” When complete, determine top 2-3 causes worth testing/investigating