SPC Procedure

SCHART Statement

  • SCHART < / options>;

The SCHART statement produces control charts for subgroup standard deviations. Table 11 lists the options that you can specify in an SCHART statement. For detailed descriptions of these options, see the section Dictionary of Options.

Table 11: SCHART Statement Options

Option Description
ALLN Includes all subgroups in the analysis, regardless of sample size
CIINDICES Computes capability index confidence limits
EXCHART Produces results only for charts in which exceptions occur
LIMITN= Specifies the nominal sample size for fixed control limits
NO3SIGMACHECK Enables tests for special causes to be applied when control limits other than limits are in effect
NOPRINT Suppresses ODS output
OUTLIMITS= Creates an output data table that contains control limits
OUTTABLE= Creates an output data table that contains subgroup summary statistics and control limits
SIGMAS= Specifies the width of the control limits in terms of a multiple of the standard error of the subgroup summary statistic
SMETHOD= Specifies the method of estimating the process standard deviation
SPECS= Specifies an input data table that contains process specification limits and computes process capability indices
TEST2RUN= Specifies the length of the pattern for Test 2
TEST3RUN= Specifies the length of the pattern for Test 3
TESTNSTD Applies tests for special causes to standardized chart statistics
TESTOVERLAP Performs tests for special causes on overlapping patterns of points
TESTS2= Requests tests for special causes for the s chart


Last updated: May 14, 2026