What is the problem?
Behavioural sciences are becoming more popular in developing countries. The method of choice are randomised contol trials (RCTs) that involve respondents to make a choice based on a presented stimuli (e.g picture, framed message, sound etc.)
I have not found a good solution to randomise stimuli that can then be presented to interviewees. I know that one could draw a random number from an uniform distribution, but this is problematic: the sample sizes of each condition would not be equal (especially for smaller samples).
Anything else we should know or have?
I think there could be an easy solution to this. I have however not found a feature in XLS that does it.
It would work with a function that draws one value (e.g. "3") out of a vector/"urn" (e.g [1,2,3,4]) without replacement. So next time the code is run on the device there are just three numbers in the vector/"urn" to draw from (e.g [1,2,4]). As soon as the vector/"urn" is empty it is refilled with all values. This would require the vector to be safed and adapted over interview sessions.