Using SPSS and PASW/SPSS syntax
What Is Syntax?
Syntax is computer programming language. SPSS use a specific form of syntax that is unique to SPSS. Although the nature of SPSS does not require that you utilize syntax, it can be your friend. Knowledge of syntax is particularly beneficial if you are repeating the same task in SPSS with different variables; it can save you from tedious, repetitive clicks.
Starting Simple: Frequency Tables
Using the example data set on genetic counselors, suppose you want a frequency table for the variable “attend” because you want an idea of how often genetic counselors are attending religious services. In SPSS click “Analyze” → “Descriptive Statistics” → “Frequencies” (this is covered in more depth in Chapter 14). Select the variable “attend.” After you click “continue,” this should show up in your output window:
Now, suppose you want a frequency table of the variable “relig” in order to see what religions many of the genetic counselors identify with. You could repeat the above procedure but choose “relig” instead of “attend.” Or you can use syntax.
To begin using syntax, go to “File” → “New” → “Syntax,” like this:
A new white window will pop up that looks like this:
This window is the Syntax Editor window and it allows you to control the many statistical tests available in SPSS (and many other functions) using programming language rather than point and click mouse movements.
One of the easiest ways to get started using syntax is simply to change your Preferences in SPSS to include syntax in the Output Window (see Chapter 7). You can then use that syntax to run the same commands or similar commands in the Syntax Editor window.
Returning to the example... Since we want to run the frequencies on the variable “relig,” we can start by returning to the original output window where you can copy the syntax from your original command just above the frequency table. The syntax is located in the red box below:
To copy the syntax, you will have to double-click on it, then select it and hit CTRL+C (the copy command in most operating systems). Now return to the Syntax Editor window and paste the syntax into the blank syntax window you have already opened, it should look like this:
While it is beyond the scope of this chapter to explain all of the syntax commands available in SPSS, the above commands are relatively straightforward. Let's begin with the first word:
This is a command that will tell SPSS which statistical test to perform. In our case, we simply want Frequencies. The second word is paired with an equals sign and includes our variable of interest:
This is a modifier for the first word, FREQUENCIES, that tells SPSS which variables will be analyzed. The last part of the syntax simply tells SPSS how to organize the analysis and output:
The period “.” at the end of ANALYSIS tells SPSS that is the end of a series of commands, so the software knows where this small program ends.
Now, erase the word “attend” and replace it with the word “relig,” which is the name of the religious affiliation variable in our example dataset, and click the blue arrow which tells SPSS to run the syntax. The blue arrow is circled below:
The new frequency table for the variable “relig” should pop up in your output box. Voila! You have successfully run a small computer program using SPSS syntax. Your output window will now have frequencies for both variables and should look like this:
Another Example: ANOVA
This same idea of copying the syntax and using it in the Syntax Editor to quickly run repetitive tasks can be illustrated using several of the variables in the example data set. Let's pretend you want to know if the religiosity of genetic counselors varies by their attitudes towards women obtaining abortions. In our sample data set there are seven variables examining attitudes toward abortion, each for a different reason. You could run the ANOVA seven times, pointing and clicking through the menus each time for each of the seven abortion attitudes variables. Or you can run it once, copy the syntax, paste it six times into the Syntax Editor, and simply replace the independent variable with the other six abortion attitude variables.
To run the initial ANOVA, click “Analyze” → “Compare Means” → “One-Way Anova” (covered in more detail in Chapter 21). For the dependent variable, you would select “relscale” and in the “Factor” box (which is where the independent variable goes), put the first abortion attitudes variable, “abpoor.” Run the test and you'll see this:
Now, if we wanted to see if the religiosity of genetic counselors varies by their attitudes towards women getting abortions because they are single and do not wish to marry the father of their unborn baby (“absingle”), we begin by copying and pasting the syntax from the ANOVA statistical test in the Output Window into the Syntax Editor window. Replace the variable “abpoor” with the variable “absingle.” The syntax window should look like this:
If you wanted to, you could also copy this syntax and paste it five more times, then replace the abortion attitudes variable in the syntax each time. When you're ready, run the test, click “Run.” (Note: You can run all six tests at one time by highlighting them all and selecting “Run”.) In your Output Window you should see this:
Once again, genetic counselors' religiosity varies by their abortion attitudes. However, regardless of whether or not the results show there is no significant relationship, what is important is that you can save time and energy by using syntax, particularly when you have a repetitive task you need to run many times. This chapter has only scratched the surface of syntax in SPSS; it can be used to run the entire program, avoiding the Data Editor window almost entirely. It should also be noted that other statistical software, like SAS and R, rely much more heavily on syntax. SPSS is known for being more user-friendly as it allows people to point and click to run tests.
Chapter contributed by Victoria Blyde.