I am to make a series of concept travelpackages (attributes and attribute notes/levels). This far I've got things under control - I've reduced the number of packages from 81 to 9, with the help of 'orthogonal' design.

These 9 packages have been rated by some people (1-10), on a questionnaire.

Then I've been asked to write a syntax which evaluates my conjoint plan:

CONJOINT PLAN= 'C:\Users\MYNAME\DROBBOXFOLDER\Conjoint_cards.SAV'/DATA='C:\Users\MYNAME\DROBBOXFOLDER\Respondents.SAV'/SCORE=Card_1 TO Card_9/SUBJECT=ID/FACTORS= SMS Minutter Data Tryghed/PRINT=ALL/PLOT=ALL.

However I keep getting this error:

SUBJECT SUBCOMMAND -- Subject variable is not on data file.

Execution of this command stops.