Reply To: Group Columns – distribution

PennController for IBEX Forums Support Group Columns – distribution Reply To: Group Columns – distribution


Yes, it’s a general concern with Ibex’s default handling of the internal counter. Maybe next releases of PennController should replace the default behavior so it increments the counter at the very beginning of the experiment instead, but I’m afraid that people used to the original Ibex wouldn’t notice the change and make the wrong assumptions.

In any case, you have multiple solutions:

  1. You can manually set the counter using PennController.SetCounter (place its label where you see fit in your sequence of trials, probably at the very beginning or immediately after the welcome screen)
  2. You can replace experiment.html in your experiment’s URL with where N is a number from 0 to the total-1 of different values appearing in your Group column. Then you have two options:
    1. You collect data in as many batches of participants as different N-based links (this is what I usually do: I collect one batch of participants, then update the link and collect another batch).
    2. You find a solution to automatically fill N, for example passing the participant’s ID in its place if the ID is a number: N is modulo-based so if your participants’ IDs are evenly distributed, you should get a reasonable output distribution.

    Let me know if you have questions