Column to Identify Control Rows in the EDDS Use this field to specify the column in the EDDS whose levels define the controls for each batch. To Specify the Column That Identifies the Control Rows: Specify an Experimental Design SAS Data Set. All of the variables in the EDDS are displayed in the Available Variables field. Examine the list of available variables. Highlight the variable whose values identify the control rows. Click to add the highlighted variable to the Column to Identify Control Rows in the EDDS field, as shown below: Note: You must specify the value that identifies the control using the Value of Columns above to Be Associated with Control parameter.