NIPO ODIN Version 5.17
Filters
The command *IF can be used to specify a logical expression. With this command it is possible to exclude certain combinations of levels (within the same profile or between 2 profiles), or to the contrary, levels can be defined (which means that certain levels always have to appear together).
*IF <[expression]>
This command can be inserted only once between *CONJ and *ENDCONJ, but the expression itself can run over several lines. Furthermore it is possible to insert references in the expression which refer to questions outside the Conjoint module.
Two lists are identified in the comparison, and they are referenced as A-list and B-list. It is not of any importance whether they appear on the screen on the left or the right. Directly after the list reference the number of the description of the list are specified. For example, ?A2 refers to list 2, and ?B"price",3 refers to the third code of the list called price.
The meaning of a filter expression like *IF [#(?A2,4 & ?B"price",3)] is: code 4 from list 2 (at one side of the screen) and code 3 from the list called "price" (at the other side of the screen) may not appear at the same time.
The use of the command *IF is in principal excluding, which means it prevents the appearance of two levels at the same time on the screen. If used for including, which means two levels always have to appear on screen together, it has to be defined for "left" and for "right":
*IF [ ( ?A2,1 & ?A3,1 ) \ ( ?B2,1 & ?B3,1 ) ]
This filter specifies that level 1 of feature 2 and level 1 of feature 3 must always appear together, for both sides of the screen.
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