Hi everybody,

I'm trying to run an experiment with real time interaction among participants (that is, a game) online (rather than in a physical laboratory). The game has multiple rounds (e.g., multiple repetitions of the same stage game). To minimize the impact of one participant abandoning the experiment midway through (and "orphaning" at least one other participant who'd be willing to complete the experiment), I'm wondering whether there is any way to replace dropped out participants with new participants on the fly (with the new participant taking the place of the drop out in the matching assignment)? 

Thank you!

Salvo Nunnari

Hi Salvo,

My two cents.

Although I think that rematching with spares in case of dropouts is undesirable in the majority of designs, there a few ways to do that.

A simple one would be to have spares that are kept on a waiting page - with group by arrival time = True - where all active participants land at the beginning of each round. On that page you can check whether P1's partner has dropout: if no, the pair is preserved, else P1 is matched with a spare or another orphan. Once all active participants have passed that waiting page, all spares are moved to the waiting page of the next round.

Best