In my study, I am building a survey with a database of 3 stimuli (Image 1, Image 2, Image 3).
My design is to have two randomisations. Firstly, it will randomly assign one of the three images to a participant for evaluation. At the end of the survey I would ask whether the participant would like to evaluate another image. If the answer is yes, then another image would be assigned randomly to him/her, but excluding the one image that was evaluated previously.
Example:
First Randomization of the whole set (Image 1, Image 2, Image 3) - participant is assigned to and evaluates Image 1
Second Randomization of the sub set excluding Image 1 ( Image 2, Image 3) - participant would evaluate the randomised result of Image 2 or Image 3
The (first) whole set of images and the (second) sub set of images will have to be built into two separate blocks, due to the need of the survey flow.
Is this design possible? Especially, how to condition the second randomization based on/by excluding the outcome option of the first randomization?
It would be great to hear about your solutions (in detailed steps). Browsing all available answers posted in the community so far did not help much. I appreciate your support!
Best answer by CarolK
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