Experiments Flashcards
What is “control’?
Being able to manipulate one behavioural factor of interest while holding all other factors constant
What are the three methods for constructing a counterfactual?
Difference in differences
Propensity matching
Laboratory experiments
What assumptions are required to hold for the difference in differences model to provide a valid counterfactual?
Parallel trends assumption, observed and unobserved characteristics remain constant over time.
Groups respond to treatment the same way.
One group cannot be exposed in isolation to a third factor.
What is propensity matching?
Subjects are matched by the probability of being treated using a profit estimator. Treated are compared to untreated, with equal probability scores.
What assumptions are required for propensity matching to produce a valid counterfactual?
Treatment and control groups are the same in absence of the treatment.
Treatment and control groups respond in the same way to the treatment.
Neither group can be exposed in isolation to a third factor.
Unobserved characteristics are the same for treated and untreated.
What assumptions must be met for a laboratory experiment to produce a valid counterfactual?
Treatment and control groups must be the same in absence of the treatment, on average.
Groups should respond to treatment in the same way.
Groups cannot be exposed in isolation to a third factor.
What does control solve for?
Confounds
What does randomisation solve for?
Selection bias.
What 3 qualities mean that experiments allow causal inference?
The counterfactual can be observed.
Control means there are no confounds.
Randomisation eliminates selection bias.
What 5 precepts achieve control?
- Non-satiation.
- Salience.
- Dominance.
- Privacy
- Parallelism
Describe non-satiation
Given a costless choice, more of the reward medium is always preferred to less.
Describe salience
The reward structure matches performance. Better performance leads to greater rewards. These promised rewards are honoured by the experimenter.
Describe dominance
The reward structure outweighs and subjective costs of participating in the experiment
Describe privacy
Subjects are only given information regarding their own payoffs, unless explicitly part of the hypothesis being tested.
Describe parallelism
Subjects and institutions in the lab are expected to behave similarly outside the lab, given similar ceteris paribus conditions.
What two precepts satisfy an Economic experiment?
Non-satiation and salience