SAS Helpful Hints

Biostat Macro Library

Mass Production of Standard Error Plots

%StdErrPlot and %StdErrPlotY reside in the departments SAS Macro Library and are enabled with the following SAS statements:

Libname biostat '\\BIO2\example\SASMacrosWindows';
Options Mstored SasMstore=biostat;

%StdErrPlot and %StdErrPlotY calculate and plot the standard error bars of the changes from baseline, by treatment, for each variable listed. Visits that have <20% of enrolled subjects are automatically dropped. Available plot styles are BlackWhite, Color (white background) or PowerPoint (blue frame, gold trim, black background). Graphs are displayed individually and 2, 4, 9 or 16 to a page. “Jitter” allows you to space out the error bars so they are not printed directly on top of each other.

Syntax:
%StdErrPlot(dataset,who,group,visit,baseline,start,stop,by,jitter,varlist,style,replay);
%StdErrPlotY(dataset,who,group,visit,baseline,start,stop,by,jitter,ystart,ystop,yby,varlist,style,replay);
    dataset:   Dataset to use.
    who:       Subject ID.
    group:     Group/Treatment(Numeric).
    visit:        X axis/Time/Week/Month(Numeric).
    baseline:  Baseline visit(Numeric Constant).
    start:        X axis Begining(Numeric Constant).
    stop:        X axis Ending(Numeric Constant).
    by:           X axis Step(Numeric Constant).
    jitter:        Space between standard error bars(Numeric Constant).
    varlist:      List of variables to Boxplot(Numeric).
    style:        BlackWhite, Color or PowerPoint.
    replay:      Number of graphs to display on a page(2, 4, 9 or 16).
    ystart:       Y axis Begining(Numeric Constant).
    ystop:       Y axis Ending(Numeric Constant).
    yby:          Y axis Step(Numeric Constant).

Example:
%StdErrPlot(work.A,id,treatment,visit,0,-2,12,2,0.1, A B C D E,Color,9);
%StdErrPlotY(work.A,id,treatment,visit,0,-2,12,2,0.1,-15,20,5,A B C D E,Color,9);

The default colors may be changed by defining a macro variable named “Colors”:

%Let Colors=Background_color Foreground_color Group1_color Group2_color Group3_color…;
%Let Colors=Blue Yellow Green Red Purple Black;

The default font of centx may be changed on all text by defining a macro variable named “Font”:

%Let Font=Simplex;

The position of the legend may be changed by defining a macro variable named "LegendOption":

%Let LegendOption=Position=(Inside Top Left) Across=2 Down=2;

This procedure creates a graphics catalog named “work.mplot”. The graphics catalog may be cleared by closing the graph window and running the following code.

Proc Datasets Library=work Memtype=Catalog;
    Delete mplot;
Run;

If you are running SAS interactively, this procedure will always replay the first set of graphs in the catalog. You may wish to reset the catalog between each procedure call.

Output:

%StdErrPlotY allows you to fix the Y axis to compare similar scales.

*Usage Trick: If you have a few sets of graphs with fixed Y axis, they may be replayed together by padding
the variable list in the last call to %StdErrPlotY:

%StdErrPlotY(work.A,id,treat,visit,0,-2,12,2,0.1,-15,20,5,A1 A2,Color,9);
Creates two graphs and saves them in a SAS catalog.

%StdErrPlotY(work.A,id,treat,visit,0,-2,12,2,0.1,-4,16,4,B1 B2 B3,Color,9);
Creates three graphs and saves them in the SAS catalog. The catalog now has five graphs.

%StdErrPlotY(work.A,id,treat,visit,0,-2,12,2,0.1,-3,9,1,C1 C2 C3 C3 C3 C3 C3 C3,Color,9);
The above statement creates eight graphs and saves them in a SAS catalog. The catalog now has 13 graphs. The last five are obviously repeated. Since there are 8 variables in the variable list, the macro will only replay the first 8 graphs from the catalog and ignore the last 5 repeated graphs. As long as the catalog is not cleared, StdErrPlotY can replay all the graphs saved in the catalog.

Please send your comments and suggestions about this web page to A. Watts (watts@bst.rochester.edu)