Randomly present n of x treatments?
Randomly present n of x treatments?
[edited from support email]
I have a 10 treatment within subjects design and I would like to randomize the order that the treatments are presented. This seems pretty easy to do in MediaLab. However, due to time constraints, subjects will only be able to respond 5 of the 10 treatments. Is there any way for me to create an experiment where 5 treatments (out of the 10) randomly appear to each subject?
Are these treatments items within a single questionnaire, or is each one an entire questionnaire?
I think I can do it either way. There is a definition, followed by 6 questions about the definition. Each definition is on an instructions page, followed by the 6 scale response questions.
Great, then I would put them all in 1 questionnaire. Assign all the items of each treatment the same BGR value. This will randomize the order of the treatments while maintaining the order of the items within treatments. After the first 5 treatments, insert a simple Instruction item that has a skipto value of "end" or perhaps a debriefing screen you have as the last item in your session. Give it a BGR value of 0 as well as that final item. That will do it.
The idea is that all the treatments will be randomly ordered, but the experiment will skip to the end after the first 5. Voilà! See unconditional skipping in the randomization sections of the user guide for more detail.
Hope that helps,
Blair
