Payment limits

To increase robustness regarding payments, e.g. in the case of coding errors, two default payment limits exist in PsyNet:

• max_participant_payment which limits how much an individual participant can be paid, the default of which is $25.00, and

• soft_max_experiment_payment which sets a soft limit on how much the experiment can cost overall. Once the amount of accumulated payments (incl. time and performance rewards) in US dollars exceedes the limit the recruiting process stops. It is a soft limit in the sense that the limit can still be exceeded to a certain extent. The default is $1000.00.

• hard_max_experiment_payment which sets a hard, absolute limit on the amount spent in an experiment. Bonuses are not paid from the point the value is reached and the amount of unpaid bonus is saved in the participant’s unpaid_bonus variable. Additionally, the experimenter is notified about the issue. Default: 1100.0.

All limits are implemented as class attributes and can be overridden in the definition of the Experiment class of an experiment by assigning some float value, e.g.:

class Exp(psynet.experiment.Experiment):
    variables = {
        "max_participant_payment": 10.0,
        "hard_max_experiment_payment": 550.0,
        "soft_max_experiment_payment": 500.0,
    }

Also, in all cases emails are sent out should the limit be exceeded notifying the user about the reduction of the payment for a participant or about the termination of the recruiting process.