Using the FACTEX Procedure Interactively

By using the FACTEX procedure interactively, you can quickly explore many design possibilities. The following steps provide one strategy for interactive use:

1. Invoke the procedure by using the PROC FACTEX statement, and use a FACTORS statement to identify factors in the design.

2. For a design that involves blocking, use the BLOCKS and MODEL statements. You might want to use the optimization features for the BLOCKS statement.

3. For a fractional replicate of a design, use the SIZE and MODEL statements to specify the characteristics of the design. If the design involves blocking, use a BLOCKS statement as well. If you are unsure of the size of the design or of the number of blocks, use the optimization features for either the BLOCKS or SIZE statement.

4. Enter a RUN statement and check the SAS log to see if the design exists. If a design exists, go on to the next step; otherwise, modify the characteristics given in the SIZE, BLOCKS, and MODEL statements.

5. Examine the alias structure of the design. If it is not appropriate for your situation, go back to step 2 and search for another design.

6. After you have repeated steps 2, 3, and 4 and found an acceptable design, use the OUTPUT statement to save the design. You can optionally recode factor values, recode and rename the block factor, and create new factors by using output-value settings.