Summing rescored scales in SPSS
Suppose we have three items in a questionnaire taking values between 1 and 4. Scores of 3 or 4 on scales q1 and q2 and 1 or 2 on scale q3 correspond to clinical depression. We wish to re-code these items into depressed or not depressed and sum over them. Both these operations can be done simultaneously using the count command.
This can also be accessed from the menu using transform…count….
Alternatively we can open a syntax window by going to File…New…syntax…. and simply typing in:
count depress = q1 q2 (3,4) q3(1,2). freq var depress.
We can compute more than one total scale score using the same command. For example to create depression and anxiety scores by summing dichotomised items:
count depress = q1 q2 (3,4) q3(1,2) /anxiety= q4(3,4) q5(1,2). freq var depress anxiety.
We separate each summation with a slash.
We can flag cases with one or more item missing values:
count x=q2 to q5 (missing) freq var x.
and then just use complete cases:
temporary. select if x=0. freq var depress anxiety.
Syntax can be run from the menu bar or by positioning the cursor at the end of the syntax and pressing Ctrl and R.