Quality and Reliability Methods - SAS

132 Assess Measurement Systems Chapter 8
Measurement Systems Analysis Platform Options
Shift Detection Profiler
The Shift Detection Profiler shows you the probability of getting a warning on your process behavior chart,
based on the settings in the profiler.
The profiler settings include the following:
Number of Subgroups
on Wheeler’s tests.
shows how many subgroups you are measuring. This number is set to 10 based
Part Mean Shift shows a shift in the mean, set to detect a 1 sigma shift by default. The initial value
reflects the standard deviation of the part component, found in the variance components report.
Part Std Dev shows a shift in the variance. The initial value reflects the standard deviation of the part
component, found in the variance components report.
Bias Factors Std Dev shows the average shift of nuisance factors, not including part, and pure error. The
initial value reflects the reproducibility standard deviation, found in the EMP Gauge R&R report.
Test-Retest Error Std Dev shows the shift in measurements from one operator measuring one part over
and over. The initial value reflects the standard deviation of the within component, found in the
variance components report.
Subgroup Sample Size shows the sample size number, set to 1 by default.
You can change these settings to see how the probabilities are affected. You can also select and customize the
tests that you want to apply when profiling. The probability of detecting warnings increases as you add
more tests.
Related Information
• For more information about tests, see “Nelson Rules” on page 39 in the “Statistical Control Charts”
chapter.
• For more information about the Variance Components report and the EMP Gauge R&R report, see the
“Variability Charts” chapter on page 151.
• For more information about the Profiler and associated options, see Modeling and Multivariate Methods.
Bias Comparison
The Bias Comparison option creates an Analysis of Means chart. This chart shows the mean values for
each level of the grouping variables and compares them with the overall mean. You can use this chart to see
whether an operator is measuring parts too high or too low, on average.
The red triangle menu next to Analysis of Means contains the following options:
Set Alpha Level select an option from the most common alpha levels or specify any level using the Other
selection. Changing the alpha level modifies the upper and lower decision limits.
Show Summary Report shows a report containing group means and decision limits, and reports if the
group mean is above the upper decision limit or below the lower decision limit.