![pages.py
In pages.py we create the pages that will be shown to the user, define the
forms, expose variables for the front end and so on.
1 # Class for the IntroPage. Inherits attributes from Page Class
2 class IntroPage(Page):
3 # Get forms to be displayed on IntroPage
4 form_model = 'player'
5 form_fields = ['name', 'risk']
We register the fields that will be exposed on the front-end, and the
variables that will be stored in each ’player object’
4](https://image.slidesharecdn.com/presentation-191215135548/85/Implmenting-an-Experiment-in-oTree-7-320.jpg)
Implmenting an Experiment in oTree
- 1. Implementing an experiment in oTree Olaf Ghanizadeh
- 3. What is oTree? • Open Source framework to create behavioral economics experiments, Chen, Schonger, and Wickens (2016). • Python based, uses Django to create a web application • Bootstrap 4 for styling • Object-oriented, extensive use of classes and methods 1
- 4. How does oTree work?
- 5. Templates In models.py we execute most of our code: 1 class Subsession(BaseSubsession): 2 """Create the session to be played""" 3 def creating_session(self): 4 """Create variables that holds for all players in this session""" 5 for p in self.get_players(): 6 """Each player, p, in the session, self""" 7 8 class Group(BaseGroup): 9 """If we wanted to have players in different groups""" 10 pass 2
- 6. models.py In models.py we execute most of our code: 1 class Player(BasePlayer): 2 """We execute what goes for each player.""" 3 name = models.StringField() We register the fields that will be exposed on the front-end, and the variables that will be stored in each ’player object’ 1 def set_payoffs(self): A method within the Player Class where we can set the payoff for each player. We need to call this method for payoffs to be set. In my project it is called before the user sees the final results page. 3
- 7. pages.py In pages.py we create the pages that will be shown to the user, define the forms, expose variables for the front end and so on. 1 # Class for the IntroPage. Inherits attributes from Page Class 2 class IntroPage(Page): 3 # Get forms to be displayed on IntroPage 4 form_model = 'player' 5 form_fields = ['name', 'risk'] We register the fields that will be exposed on the front-end, and the variables that will be stored in each ’player object’ 4
- 8. pages.py 1 # Class for the DecisionPage. Inherits attributes from Page Class 2 class DecisionPage(Page): 3 form_model = 'player' 4 5 ... 6 7 # Triggers the function that set draws the payoff of the 8 #user before the user is taken to the result page. This 9 # should be changed if we were to make a game with several rounds. 10 def before_next_page(self): 11 self.player.set_payoffs() We call the self.player.set_payoffs() before the next page is loaded to set the payoffs for the individual player. 5
- 9. Templates • HTML Templates • Dynamic through Django template tags and variables • Extensible with JavaScript. 6
- 10. Experiment
- 11. Experiment • A simplified version of the experiment made famous in Holt and Laury (2002). • An approach to elicit individual preferences for risk, and how incentive effects affect choices. • Assumes that utility theory holds. 7
- 12. Our goal Does the participant choose differently from their indicated risk preferences? 8
- 13. • A risk-neutral user should consider the expected values of the different outcomes, and maximize it for each choice. • In our experiment that is the sequence AAAA/BBBB 9
- 14. Acknowledgements
- 15. Acknowledgements • Severly simplified version of experiment • Should record at what point the user decides to switch from A to B • Code error with > 9 choices. • Should include several rounds and treatments • Lacks calculation of Constant Relative Risk Aversion (CRRA) 10
- 16. Data Analysis
- 17. References Chen, Daniel L., Martin Schonger, and Chris Wickens (Mar. 2016). “oTree—An Open-Source Platform for Laboratory, Online, and Field Experiments”. In: Journal of Behavioral and Experimental Finance 9, pp. 88–97. issn: 22146350. doi: 10.1016/j.jbef.2015.12.001. url: https: //linkinghub.elsevier.com/retrieve/pii/S2214635016000101 (visited on 12/04/2019). Holt, Charles A and Susan K Laury (Nov. 2002). “Risk Aversion and Incentive Effects”. In: American Economic Review 92.5, pp. 1644–1655. issn: 0002-8282. doi: 10.1257/000282802762024700. url: http://pubs.aeaweb.org/doi/10.1257/000282802762024700 (visited on 12/04/2019). 11
- 18. Questions? 11