Quality Improvement Course

Cause and effect/Fishbone/Ishikawa Diagram

Definition: A graphic tool used to explore and display opinion about sources of variation in a process. (Also called a Cause-and-Effect or Fishbone Diagram.)

Cause-and-Effect Template:

Purpose: To arrive at a few key sources that contribute most significantly to the problem being examined.  These sources are then targeted for improvement.  The diagram also illustrates the relationships among the wide variety of possible contributors to the effect.

This example shows a simple Ishikawa diagram of the delays encountered by Internal Medicine residents when discharging patients.

Note that this tool is referred to by several different names: Ishikawa diagram, Cause-and-Effect diagram, Fishbone diagram, and Root Cause Analysis.  The first name is after the inventor of the tool, Kaoru Ishikawa (1969) who first used the technique in the 1960s

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