Syntax Raw Score and Missing Values

#1
Hi, I am trying to calculate the raw score of a 76 item, 4 point likert scale questionnaire. First, a subscore has to be calculated, for example,

DATASET ACTIVATE DataSet1.
COMPUTE NewVar=SS_49AT3 + SS_52AT3 + SS_56AT3 + SS_59AT3 + SS_63AT3.
EXECUTE.

However, from here I need to know how many values were missing out of the SS variables and if possible create a new variable with the count. Then I multiple the count by 2 then subtract from what the sum of the "NewVar". However, I am not sure what the correct syntax would be.

I have the following drafts:
COUNT MISSING=SSI_49AT3 to SS_63AT3 (999) . or COMPUTE NMISS=NMISS?

Any help would be appreciated! Also the missing values are user defined 999
 
#2
If you have it defined that 999 is missing, SPSS will not include it in its syntax file, hence it won't work. Remove that definition under missing values for those variables, than run the following:

COUNT MISSING=SSI_49AT3 to SS_63AT3 (999)

Regarding your sum, SPSS will not calculate it if there's a missing value at any of the variables for each row. You'll therefore need to turn the missing to 0.