Reply To: Pseudoranomization

PennController for IBEX Forums Support Pseudoranomization Reply To: Pseudoranomization


Hi Jeremy,

I’ve run into some problems with randomization now. Back in October, I uploaded a table with the three groups (like I mentioned above in my first posts), groups A, B, and C. I was able to get it to randomize the group presentation with randomize(“experiment”), and it only ever presented stimuli from group A, B, or C; never all three. In my results file, I could see that the participant received group B’s stimuli, group A’s, stimuli, etc. That .csv file was entitled StimuliTemplate2.csv.

I’ve since created some new tables (like the one that I’m using to figure out pseudorandomization) and they are more or less the same as StimuliTemplate2. However, when I’m using these tables, all groups end up getting presented in the experiment. So all stimuli from groups A, B, and C get presented. Really the table “StimuliTemplate2.csv” is the only one where stimuli is presented from only one group, despite the fact that I’m using nearly the exact same script (at some points I’ve cut out the practice trials and gone right to the experiment, but otherwise the script remains the same). I’ve revised the newer tables multiple times: I’ve added information into the “trial_ID” column so that all columns are filled out, and I’ve added rows into each group so there is an even and equal number of stimuli in each group (i.e eight congruent flankers in group A, eight in group B, etc). Nothing I try seems to fix the problem.

Do you have any idea what might be causing these issues?

Thank you!