from otree.api import * c = cu doc = "\nEach player decides if to free ride or to volunteer from which all will\nbenefit.\nSee: Diekmann, A. (1985). Volunteer's dilemma. Journal of Conflict\nResolution, 605-610.\n" class Constants(BaseConstants): name_in_url = 'volunteer_dilemma' players_per_group = 3 num_rounds = 1 num_other_players = 2 general_benefit = cu(100) volunteer_cost = cu(40) instructions_template = 'volunteer_dilemma/instructions.html' class Subsession(BaseSubsession): pass def set_payoffs(group): players = group.get_players() group.num_volunteers = sum([p.volunteer for p in players]) if group.num_volunteers > 0: baseline_amount = Constants.general_benefit else: baseline_amount = c(0) for p in players: p.payoff = baseline_amount if p.volunteer: p.payoff -= Constants.volunteer_cost class Group(BaseGroup): num_volunteers = models.IntegerField() class Player(BasePlayer): volunteer = models.BooleanField(doc='Whether player volunteers', label='Do you wish to volunteer') class Introduction(Page): form_model = 'player' class Decision(Page): form_model = 'player' form_fields = ['volunteer'] class ResultsWaitPage(WaitPage): after_all_players_arrive = 'set_payoffs' class Results(Page): form_model = 'player' page_sequence = [Introduction, Decision, ResultsWaitPage, Results]