Quick Guide to Good Programming Practice

Programming style:

• Use a standard program header. It should contain names of program, programmer and date first completed, purpose and revision history.
• When writing program keep in mind that it will need to be changed. Can you follow it after one year?
• Use different Comment style to split programs into sections (input, process, output) so they stand out in the program. Write comments in the form * Comments *; and avoid /* comments */, ideally within a box. If an existing program has /* comments */ then use %MACRO donotuse; and %MEND donotuse; to comment out sections of the program.
• Explain algorithm and logic in a comment box just before data steps and procedures.
• Avoid inserting comments inside DATA steps or PROC SQL steps, put them in a box above the data step. It makes the program easier to read.
• Set up program into INPUT, PROCESS and OUTPUT sections.
• Read in all external data ONLY ONCE. Do this at the top of the program in the INPUT section.
• Use “KEEP=” to list variable names when reading (INPUT) and writing (OUTPUT) external datasets.
• Only write ONE SAS statement per line.
• Use different meaningful names for each temporary dataset.
• Use indentation. Indent 2 characters (or one tab), but remain consistent throughout the program.
• Use Uppercase for SAS KEYWORDS to make programs easier to read.