The _OBSTAT_ variable is often used in conjunction with a SAS procedure to analyze observations that satisfy certain criteria. For example, you might want to perform a linear regression only on observations that have the Include in Analysis property. Or you might want to compute a correlation matrix only for observations that are represented by a square marker shape.

The _OBSTAT_ variable contains information about the state of observations in SAS/IML Studio. It is often convenient to use the DATA step to split the single _OBSTAT_ variable into several indicator variables so that it is easier to use a WHERE clause to choose only observations that have a desired property.

To use the _OBSTAT_ variable to select observations for analysis by a SAS procedure:

1. Create an _OBSTAT_ variable by selecting Generate _OBSTAT_ Variable from the variable menu.

2. Save the augmented data to a SAS data set such as SASUSER.MyData.

3. Use the following DATA step to extract each observation property into its own variable:

   /* Create numerical variables from an _OBSTAT_ variable. */
   data MyData;
   set sasuser.MyData;
   ObsIsSelected   = inputn(substr(_obstat_,  1, 1), 1.);
   ObsIsInPlots    = inputn(substr(_obstat_,  2, 1), 1.);
   ObsIsInAnalysis = inputn(substr(_obstat_,  3, 1), 1.);
   ObsIsLabeled    = inputn(substr(_obstat_,  4, 1), 1.);
   ObsMarkerShape  = inputn(substr(_obstat_,  5, 1), 1.);
   ObsMarkerRed    = inputn(substr(_obstat_,  6, 5), 5.);
   ObsMarkerGreen  = inputn(substr(_obstat_, 11, 5), 5.);
   ObsMarkerBlue   = inputn(substr(_obstat_, 16, 5), 5.);
   run;
   

4. Use a WHERE clause to analyze only observations with a given set of properties. For example, the following statements compute a correlation matrix for observations that are represented in SAS/IML Studio by a marker shape:

   data Subset;
   set MyData(where=(ObsMarkerShape=1);
   run;
   
   proc corr data=Subset(drop=Obs:);
   run;