Hello everyone,

This is my first time using this software, and I am having trouble implementing a situation. I want to be able to randomly assign a type of form to participants. The form differs according to the treatment and the order of questions as follows:

class C(BaseConstants):
    NAME_IN_URL = 'risk_task'
    PLAYERS_PER_GROUP = None
    NUM_ROUNDS = 1
    treatments = ['T1', 'T2', 'T3', 'T4']
    treatment_parameters = {
        'T1': {'average': 80, 'ratio': 3, 'lower': 40, 'upper': 120},
        'T2': {'average': 80, 'ratio': 9, 'lower': 16, 'upper': 144},
        'T3': {'average': '2X', 'ratio': 3, 'lower': 'X', 'upper': '3X'},
        'T4': {'average': 160, 'ratio': 9, 'lower': 32, 'upper': 288},
    }


class Subsession(BaseSubsession):
    def creating_session(self):
        import random
        for player in self.get_players():
            # Assign a random treatment
            player.treatment = random.choice(C.treatments)
            # Randomly assign the order of tasks
            player.task_order = random.choice(['risk_first', 'social_first'])
            
This code does not seem to work. Can you help me, please?

Thank you.

If I am not mistaken, if you are using the latest version of oTree, you should place def creating_session outside of the class Subsession.

Hi manu_oble -

What do you mean by "does not seem to work?"   What are you doing to run the code, and what result are you getting?  The more detail you can provide, the easier it is for us to help.

Thanks,
--Chris

Hi Chris, 

I have a form that needs to be assigned to multiple participants. The participants are grouped into four according to treatments T1, T2, T3, and T4. The instructions in the form contain constants that refer to the treatments. For example, for a participant in Treatment 1, the text of their form should adapt to the parameters of the respective treatment as follows: "You earn {CONSTANT.RATIO} times more than the others... If the poor earn {CONSTANT.LOWER} and the rich {CONSTANT.UPPER}". The form should change randomly each time the participant clicks on the link.


class C(BaseConstants):
    NAME_IN_URL = 'social_task'
    PLAYERS_PER_GROUP = None
    NUM_ROUNDS = 1
    treatments = ['T1', 'T2', 'T3', 'T4']
    treatment_parameters = {
        'T1': {'average': 80, 'ratio': 3, 'lower': 40, 'upper': 120},
        'T2': {'average': 80, 'ratio': 9, 'lower': 16, 'upper': 144},
        'T3': {'average': '2X', 'ratio': 3, 'lower': 'X', 'upper': '3X'},
        'T4': {'average': 160, 'ratio': 9, 'lower': 32, 'upper': 288},
    }


class Subsession(BaseSubsession):
    def creating_session(self):
        import random
        for player in self.get_players():
            # Assign a random treatment
            player.treatment = random.choice(C.treatments)
            # Assign treatment parameters
            player.treatment_params = C.treatment_parameters[player.treatment]
            # Randomly assign the order of tasks
            player.task_order = random.choice(['risk_first', 'social_first'])

class Group(BaseGroup):
    pass


class Player(BasePlayer):
    treatment = models.StringField()
    task_order = models.StringField()
    treatment_params = models.StringField()
    
    ...
    ...
    
# PAGES
class Introduction(Page):
    form_model = 'player'
    form_fields = ['consent']

class STScenario1(Page):
    form_model = 'player'
    form_fields = ['S1_Q_1', 'S1_Q_2', 'S1_Q_3', 'S1_Q_4', 'S1_Q_5', 'S1_Q_6', 'S1_Q_7', 'S1_Q_8', 'S1_Q_9', 'S1_Q_10', 'S1_Q_11']

    def is_displayed(player: Player):
        # Affiche uniquement si le consentement est donné
        return player.consent == True
        
class STScenario2(Page):
    form_model = 'player'
    form_fields = ['S2_Q_1','S2_Q_2','S2_Q_3','S2_Q_4','S2_Q_5','S2_Q_6','S2_Q_6','S2_Q_7','S2_Q_8','S2_Q_9','S2_Q_10','S2_Q_11','S2_Q_12']

    def is_displayed(player: Player):
        # Affiche uniquement si le consentement est donné
        return player.consent == True
        
page_sequence = [Introduction, STScenario1, STScenario2,]

Hi manu_oble -

Thank you for the description of what you need.

What is happening when you run things that makes you say it "does not seem to work?"  Are you getting error messages?  Is the wrong thing showing up in your browser?  Are you not getting the data you expect in your subjects' model fields?

The more detail you can provide, the more likely it is we can help.

Thanks,
--Chris

Hi Chris 

When I run it, the error occurs at the HTML pages where there are texts containing the constants.
Here is the error: Application error (500) UndefinedVariable: Cannot resolve the variable 'ratio' (line 8, in "ratio").

I thought about creating a variable "Traitement" which would take the values T1, T2, T3, and T4. Then, in the HTML files, create conditional texts. That is, when Traitement = T1, the constants in the text take the values of T1's parameters.
But I don't know how to formalize this.