Discrimination Plot

The Discrimination Plot (or Intraclass Correlation Plot) is not one which is described in the AIAG MSA manual, but is described in Wheeler & Lyday.  The discrimination plot gives us an immediate picture of the ability of our measurement system to discriminate between different levels of the parameter being measured.  The discrimination plot obtained from the AIAG example data set is shown below:

Discrimination Plots are extremely useful in MPE studies: a discrimination ratio > 4 is generally indicative of a capable measurement process.