Difficulty creating counterbalance blocks in online experiments


I have difficulty creating counterbalance blocks in online experiments.
Is there an example of such an experiment that I can learn from? Or a simple explanation?


Do you mean randomly presenting some participants with A then B and some with B then A?

If you want equal numbers of participants to be presented with each order, then you should use my VESPR Study Portal. This could be used to send a variable called group to your study with values 1 or 2.

If A and B are loops then you could have three loops A1 with nReps a1, B with nReps 1 and A2 with nReps a2. Then put the following code in Begin Experiment

a1 = 0
a2 = 0
if expInfo['group'] == '1':
     a1 = 1
elif expInfo['group'] == '2':
     a2 = 1
     a1 = randint(0,2)
     a2 = 1 - a1

Thanks alot. The solution fits and helps my problem.