I m currently design a partial-profile conjoint study, and find something is difficult to set up. So it would be appreciated if anyone could help me.
My study includes 11 attributes. Each attribute has 2 levels which indicate the attribute is available or not. Thus, it looks like below:
Attribute 1: Level 1 - Available; Level 2 - Unavailable
Attribute 2: Level 1 - Available; Level 2 - Unavailable
Attribute 11: Level 1 - Available; Level 2 - Unavailable
For each attribute, I want to only show "available" level which is Level 1, so I define null level prohibitions within prohibitions dialogue. I tick Level 2 (Unavailable) for each attribute, but a bit confused to set the number for minimum / maximum null levels per concept in order to meet my needs. (Currently, I set 7 for minimum, and 8 for maximum)
Also, for each concept, I want to always only show 3 attributes per concept, and 4 concepts (plus none option) per screen.
Then I go to "Advanced Design Module" dialogue, and select "Partial-profile CBC Design", and set 1 for "Rotate Attributes into Concepts Starting with", 11 for "and Ending with Attribute" in order to make full rotating attributes. Besides, 3 for "Number of Attributes Shown in each Concept".
BUT, when I press "Preview" button....
A warning dialogue pops up: The following preview error occurred: The task could not be generated according to the constraints. Please check the prohibitions.
I really don't know what I did wrong. Also, the warning dialogue pops up when I press "Generate Design" button.
I use SSI Web 6.6.12 to design this study.
My question is how to what things I did wrong, and how to solve this problem by SSI Web 6.6.12. Thanks so much for your help.