Sum also doesn't work.
You could do this:
Code: Select all
compute sum = mean (v1,v2,v3,v4,v5,v6,v7,v8,v9) * 9.
alternatively, you can set the missing values to 0 and compute a sum with those included.
Whether either of these methods make sense for your data is not possible for me to determine without knowing more about your data.