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MODULE 5

Compute Function (summary or total scores)

Task: Using the Computer Function to create a new summary variable (e.g. total scores) from a group of variables.

Start off by importing the ex3reverse.sav into the Data Editor window of PASW / SPSS (from this point forward referred to as simply SPSS). If you would like a more detailed description of our example data and the fictional situation behind it, please review (Module 4.3).

The compute function can be used to sum a series of variables such as items of a subscale on a survey.

For the example below, we will be computing a total score for our 6 item survey.

To use the Compute function, simply go to "Transform", "Compute Variable..."

You should now see the "Compute Variable" dialog box.

In the Compute dialog, first type Total_Score in the "Target Variable:" box which will be the name of our new variable. Then, type the equation in the "Numeric Expression:" box, or you can move each variable one-at-a-time and click the "+" button on the calculator pad with a space before and after each "+" to construct the equation. Now just click on "OK" or "Paste" if you would prefer a syntax record be created (from which you can highlight and submit the syntax to perform the compute/recode). Remember, it is often quicker to write the syntax for simple compute functions than it is to navigate through and point-and-click to complete the function. A review of the syntax from this example (provided in the Log portion of your output) will show how simple it would be to write such syntax.

That concludes using the Compute function to create a new variable as a sum or total score of a combination of variables.