How to Communicate with SPSS
More than one way exists for you to command IBM SPSS Statistics to do your bidding. You can use any of four approaches to perform any of the SPSS functions. The method you should choose depends not only on which interface you prefer, but also (to an extent) on the task you want performed.
The graphical user interface
SPSS has a window interface. You can issue commands by using the mouse to make menu selections that cause dialog boxes to appear. This is a fill-in-the-blanks approach to statistical analysis that guides you through the process of making choices and selecting values. The advantage of the graphical user interface (GUI) approach is that, at each step, SPSS makes sure you enter everything necessary before you can proceed to the next step. This interface is preferred for those just starting out — and if you don’t go into depth with SPSS, this may be the only interface you ever use.
Syntax is the internal language used to command actions from SPSS. It’s the command syntax of SPSS (hence, its name). Syntax is often referred to as the “command language.” You can use the Syntax command language to enter instructions into SPSS and have it do anything it’s capable of doing. In fact, when you select from menus and dialog boxes to command SPSS, you’re actually generating Syntax commands internally that do your bidding. In other words, the GUI is nothing more than the front end of a Syntax command-writing utility.
Writing (and saving) command-language programs is a good way to create processes that you expect to repeat. You can even grab a copy of the Syntax commands generated from the menu and save them to be repeated later.
Python is a general-purpose language that has a collection of SPSS modules written for it; you can use Python to write programs that work inside SPSS. You can also run Python with the Syntax language to command SPSS to perform statistical functions.
One advantage of Python is that it’s a modern language, complete with the power and convenience that come with such languages, including the capability of constructing a more readable program. In addition, because Python is a general-purpose language, you can read and write data in other applications and files. Think of Python programs as a way of making Syntax more powerful.
What SPSS calls scripts are also written in Python, but they help you manipulate the GUI. They’re a little more advanced and quite powerful. You use Python scripts to automatically highlight certain results in the SPSS output, for instance.