Converting Data Structures
In SAS and SPSS, there is only one data structure, the dataset. Within that, there is only one structure, the variable. It seems absurdly obvious, but we need to say it: all SAS and SPSS procedures accept variables as input. Of course, you have to learn that putting a character variable in where a numeric one is expected causes an error. Occasionally, a character variable contains numbers and we must convert them. Putting a continuous variable in where a categorical variable belongs may not yield an error message, but perhaps it should. Both packages have added variable classification methods (nominal, ordinal, or scale) to help you choose the correct analyses and graphs.