This works well, except for the fact that I want to make sure that individuals who are assigned to the control group only get the control in all three scenarios. My initial solution to this problem was to create a control block, in addition to the three scenario blocks where treatments are administered. However, since Qualtrics randomizes with even probabilities across blocks, this would lead to 1/4 of the participants being assigned the control scenario. Ideally, I would like to assign 1/10 of the respondents to the control group, since my most interesting comparisons for this experiment is across different treatment groups. The control is there simply to serve as a benchmark.
Is there any way to randomly assign respondents to different blocks with different probabilities?
Many thanks,
Best answer by mattyb513
View original