Many applications require input data to be in a specific format before it can be processed to produce meaningful results. Even if all of your data are already in SAS data sets, the data might come from multiple sources and might be in different formats. Therefore, you often have to take intermediate steps to logically relate and process the data before you can analyze them or create reports from them.
Application requirements vary, but there are common denominators for all applications that access, combine, and process data. Once you have determined what you want the output to look like, you must complete the following:
discover how the input data are related
select the appropriate SAS tools to complete the task