Homogenous Groups¶
In this part, we will talk about groups with homogeneous members. Which means every group member will have the same role in the game.
First let’s talk about the differences between individual tasks and such a heterogeneous group task.
Aspect |
Individual task |
Group Task |
|---|---|---|
variables/calculations |
Only my own variable |
I need to reach other peoples variables |
pages |
I can have my own pace |
Sometimes have to wait for other group members |
The Group class in oTree handles much of the structure required by groups. The number of players in a group in an app is determined by the players_per_group variable in the Constants classs in models.py.
class Constants(BaseConstants):
# ...
players_per_group = 3
# ...
By default, groups are fixed and determined by the ID of a player in a subsession (which is assigned internally). We will cover different matching procedures in the Heterogenous Groups and ./matching sections.
How those instances stand in the bigger picture¶
Fig. 5 Instances of classes: We will talk in detail on the next lectures¶
oTree object model¶
Fig. 6 Object model. Source: oTree Documentation - Conceptual Overview¶
Reaching other objects¶
Player class¶
class Player(BasePlayer):
def example(self):
# current player object
self
# method you defined on the current object
self.my_custom_method()
# parent objects
self.session
self.subsession
self.group
self.participant
self.session.config
# accessing previous player objects
self.in_previous_rounds()
# equivalent to self.in_previous_rounds() + [self]
self.in_all_rounds()
Group class¶
class Group(BaseGroup):
def example(self):
# current group object
self
# parent objects
self.session
self.subsession
# child objects
self.get_players()
Page class¶
class MyPage(Page):
def example(self):
# current page object
self
# parent objects
self.session
self.subsession
self.group
self.player
self.participant
self.session.config