PROC SHEWHART chart with phases

[Quentin]

Hi All,

I'm tyring to use PROC SHEWHART to make a control chart which computes different process limits for different phases.  Been reading the docs, and it looks like to do this I need to call PROC SHEWHART twice, and sort the data. Ugh. The first time I use OUTLIMITS to write a limits dataset, then the second time I create the chart.

Below is based on example from the SAS/QC Manual, "Displaying Multiple Sets of Control LimitsMultiple Sets of Control Limits". 

data Flange;
  input _phase_ $10. Sample FlwidthX FlwidthR FlwidthN;
  cards;
Production 6  0.97360 0.06247 5
Production 7  1.00486 0.11478 5
Production 8  1.00251 0.13537 5
Production 9  0.95509 0.08378 5
Production 10 1.00348 0.09993 5
Production 11 1.02566 0.06766 5
Production 12 0.97053 0.07608 5
Production 13 0.94713 0.10170 5
Production 14 1.00377 0.04875 5
Production 15 0.99604 0.08242 5
Change1    16 0.99218 0.09787 5
Change1    17 0.99526 0.02017 5
Change1    18 1.02235 0.10541 5
Change1    19 0.99950 0.11476 5
Change1    20 0.99271 0.05395 5
Change1    21 0.98695 0.03833 5
Change1    22 1.00969 0.06183 5
Change1    23 0.98791 0.05836 5
Change1    24 1.00170 0.05243 5
Change1    25 1.00412 0.04815 5
Change2    26 1.00261 0.05604 5
Change2    27 0.99553 0.02818 5
Change2    28 1.01463 0.05558 5
Change2    29 0.99812 0.03648 5
Change2    30 1.00047 0.04309 5
Change2    31 0.99714 0.03689 5
Change2    32 0.98642 0.04809 5
Change2    33 0.98891 0.07777 5
Change2    34 1.00087 0.06409 5
Change2    35 1.00863 0.02649 5
;
run;

proc sort data=Flange;
  by _phase_ Sample;
run;

proc shewhart history=Flange;
   xchart Flwidth*Sample /
     nochart
     outlimits=MyLimits(rename=(_phase_=_index_))
   ;
   by _phase_;
run;

proc sort data=Flange;
  by Sample;
run;

*Feed the limits dataset back into Shewhart;

proc shewhart history=Flange limits=MyLimits;
   xchart Flwidth*Sample /
      readphases  = all
      readindexes = all
      phaseref
      phaselegend 
   ;
run;

Before I proceed, wanted to make sure I'm not missing some other way to make a phased chart with just one call to PROC SHEWHART.  Feels like I want a PHASE option, pseudo-code:

proc shewhart history=Flange;
   xchart Flwidth*Sample /
      phase=_phase_
   ;
run;

Thanks,

--Q.

[Rick_SAS · Accepted solution]

I have never done this myself, but I read the syntax portion of the doc as well as the section on "Displaying Multiple Sets of Control Limits," and it looks like you are doing what the doc recommends.  The examples they give make two calls: one to create the limits and one to incorporate them,

[Quentin]

Thanks @Rick_SAS, I will mosey over and submit this as a ballot item.