1. Making a Publication-quality Graph in SAS
Bill O’Brien
COLMR Analysis Guild Presentation
February 15, 2013

2. Outline for presentation
A quick look at the Pacificare 30 day readmission measure.
Visually examine one aspect of the performance of the model.
Show the steps to make the graph ready for journal submission.

3. Pacificare Readmissions Measure
Endorsed by NQF
Logit(Pi) = а + b * RWi+ ei
Pi -> binary variable indicating if index admission i resulted in readmission (1) or no readmission (0)
RWi -> DRG weight for claim i

4. Is DRG weight predictive of readmission?
DRG RateType Rate
Actual %
Predicted %
Actual %
Predicted %
Actual %
Predicted %
Actual %
Predicted %
[...]
Model predicts anyone with DRG 605 has a 13.97% probability of readmission
Patients with DRG 605 were readmitted 13.70% of the time.

5. Illustrating correlation between predicted and actual outcome

6. Default graph ods rtf; proc gplot data=analysis.graph1t;
plot rate*DRG_order=RateType;
run;quit;
ods rtf close;

8. This graph needs work Size of chart area Title
Axes scale, labels, units
Plot symbols
Legend
Horizontal lines
Font
Borders

9. Size of chart area goptions device=gif hsize=7 vsize=4; ods rtf;
proc gplot data=analysis.graph1t;
plot rate*DRG_order=RateType;
run;quit;
ods rtf close;

11. Title
goptions device=gif hsize=7 vsize=4; ods rtf; title h=1 'Figure 1. Predicted and observed readmission rates for 718 DRGs in VA Hospitals, FY08'; footnote ; proc gplot data=analysis.graph1t; plot rate*DRG_order=RateType; run;quit; ods rtf close;

13. Axes
goptions device=gif hsize=7 vsize=4; ods rtf; title h=1 'Figure 1. Predicted and observed readmission rates for 718 DRGs in VA Hospitals, FY08'; footnote ; axis1 label=(a=90 'Readmission Rate'); axis2 order=1 to 718 by 1 label=('DRGs in Order of Predicted Rate') value=none major=none; proc gplot data=analysis.graph1t; plot rate*DRG_order=RateType /vaxis=axis1 haxis=axis2; format rate percent7.0; run;quit; ods rtf close;

15. Symbols
goptions device=gif hsize=7 vsize=4; ods rtf; title h=1 'Figure 1. Predicted and observed readmission rates for 718 DRGs in VA Hospitals, FY08'; footnote ; axis1 label=(a=90 'Readmission Rate'); axis2 order=1 to 718 by 1 label=('DRGs in Order of Predicted Rate') value=none major=none; symbol1 color=green width=1 value=x height=1; symbol2 color=blue width=1 value=dot height=1; proc gplot data=analysis.graph1t; plot rate*DRG_order=RateType /vaxis=axis1 haxis=axis2; format rate percent7.0; run;quit; ods rtf close;

17. Legend
legend1 label=('') value=('Observed Rate' 'Predicted Rate') position=(top left inside) across=1 down=2 cborder=black; proc gplot data=analysis.graph1t; plot rate*DRG_order=RateType /vaxis=axis1 haxis=axis2 legend=legend1; format rate percent7.0; run;quit;

19. Legend (alternative)
legend1 label=('') value=('Observed Rate' 'Predicted Rate') position=(bottom center outside) across=2 down=1; proc gplot data=analysis.graph1t; plot rate*DRG_order=RateType /vaxis=axis1 haxis=axis2 legend=legend1; format rate percent7.0; run;quit;

21. Horizontal lines
proc gplot data=analysis.graph1t; plot rate*DRG_order=RateType /vaxis=axis1 haxis=axis2 legend=legend1 vref=(.1,.2,.3,.4,.5,.6); format rate percent7.0; run;quit;

23. Horizontal lines (understated)
proc gplot data=analysis.graph1t; plot rate*DRG_order=RateType /vaxis=axis1 haxis=axis2 legend=legend1 vref=(.1,.2,.3,.4,.5,.6) cvref=ligr; format rate percent7.0; run;quit;

25. Font
goptions device=gif hsize=7 vsize=4 ftext=simplex;

27. Borders
goptions device=gif hsize=7 vsize=4 ftext=arial border; [...] proc gplot data=analysis.graph1t; plot rate*DRG_order=RateType /vaxis=axis1 haxis=axis2 legend=legend1 vref=(.1,.2,.3,.4,.5,.6) cvref=ligr noframe ; format rate percent7.0; run;quit;

29. Does it work in grayscale?
symbol1 color=dagr width=1 value=x height=1; symbol2 color=black width=1 value=dot

31. Before and after

32. Journal screenshot
Am J Med Qual Jul-Aug;27(4): doi: / Epub 2012 Feb 9.
Inappropriate use of payment weights to risk adjust readmission rates.
Fuller RL, Goldfield NI, Averill RF, Hughes JS.

33. SAS code for reference
goptions device=gif hsize=7 vsize=4 ftext=duplex border; ods rtf; title h=1 bold 'Figure 1. Predicted and observed readmission rates for 718 DRGs in VA Hospitals, FY08'; footnote ; axis1 label=(a=90 'Readmission Rate') ; axis2 order=1 to 718 by 1 label=('DRGs in Order of Predicted Rate') value=none major=none; symbol1 color=dagr width=1 value=x height=1; symbol2 color=black width=1 value=dot legend1 label=('') value=('Observed Rate' 'Predicted Rate') position=(bottom center outside) across=2 down=1; proc gplot data=analysis.graph1t; plot rate*DRG_order=RateType /vaxis=axis1 haxis=axis2 legend=legend1 vref=(.1,.2,.3,.4,.5,.6,.7) cvref=ligr noframe ; format rate percent7.0; run;quit; ods rtf close;