Overview: PROC CUSUM Statement

The PROC CUSUM statement starts the CUSUM procedure and it identifies input data sets.

After the PROC CUSUM statement, you provide an XCHART statement that specifies the cusum chart you want to create and the variables in the input data set that you want to analyze. For example, the following statements request a one-sided (decision interval) cusum chart:

proc cusum data=values;
   xchart weight*lot / scheme = onesided
                       mu0    = 8.100
                       sigma0 = 0.050
                       delta  = 1
                       h      = 2.2
                       k      = 0.5;

In this example, the DATA= option specifies an input data set (values) that contains the process measurement variable weight and the subgroup-variable lot. [26]

You can use options in the PROC CUSUM statement to do the following:

  • specify input data sets containing variables to be analyzed, parameters for cusum schemes, or annotation information

  • specify a graphics catalog for saving traditional graphics output

  • specify that line printer charts are to be produced

  • define characters used for features on line printer charts

In addition to the XCHART statement, you can provide BY statements, ID statements, TITLE statements, and FOOTNOTE statements. If you are producing traditional graphics, you can also provide graphics enhancement statements, such as SYMBOLn statements, which are described in SAS/GRAPH: Reference.

See Chapter 3: SAS/QC Graphics, for a detailed discussion of the alternatives available for producing charts with SAS/QC procedures.

Note: If you are using the CUSUM procedure for the first time, you should read both this chapter and the section Getting Started: XCHART Statement in XCHART Statement: CUSUM Procedure.

[26] In SAS 6.12 and previous releases of SAS/QC software, the keyword GRAPHICS was required in the PROC CUSUM statement to specify that the chart be created using traditional graphics. In SAS 7 and more recent releases, you can specify the LINEPRINTER option to request line printer plots.