Balanced condition assignment based on what other sessions have been completed

The problem is this: I have 48 different videos corresponding to different conditions, and I would like each participant to see one of these 48 videos, but not randomly. I would like to be able to administer them in a particular order - the first participant would see the first video, the n-th participant, the n-th video... etc. So the idea is to create a kind of global variable for all the experiments that allows the right video to be seen by the right participant. An idea is to use this global variable to indicate the value of whichFrames in a select-randomizer-test frame, if that's make sense.

In summary, the idea is to do assignment based on what sessions other kids have done, by storing additional (non-identifiable) data on the study model itself - e.g. something like “conditions for the last probably-usable response.”

Théo Morfoisse

Possible general approaches:
- Store an integer on the study model; each time someone participates, increment it. Allow access to this number from the API & use from the frameplayer. Provide randomizers that cycle through conditions based on the counter, and allow researchers to supply a custom function that determines condition based on the number.
- Provide an API endpoint that fetches, for a given study, summary information about the condition data in previous responses. Access this from the frameplayer. Provide randomizer options to balance conditions based on this information and allow providing custom function to do condition assignment based on response.