Week 7 :Field Experiments Flashcards
What are field experiments?
Experiments that are carried out in a field, e.g. take place in a natural setting.
What is the relationship between external validity and field experiments?
Much easier to overcome external validity issues than with lab experiments.
What is the relationship between internal validity and field experiments?
More difficult to control the environment and treatment so internal validity is generally lower than lab experiments.
What industry are field experiments popular in?
Business and NGO sector
Do field experiments raise ethical challenges?
Yes
List the 3 main ethical standards.
- Informed consent
- Benefit (for society) and no harm (for individual)
- Confidentiality
Why is there a lower internal validity in FEs?
- We cannot force people to participate so sometimes we only give the voluntary option of treatment and people willing to opt in may be a special group (less affluent)
- Sometimes, we don’t know if people actually received treatment
- Treatment may spill over to control group
- Lack of control compromises internal validity
What are the 4 different types of people involved in compliance?
Complier - treatment follows assignment
Always taker - Gets treatment regardless of assignment
Never taker - rejects treatment regardless of assignment
Defier - Does the opposite of assignment
How do we deal with defiers?
Assume that defiers don’t exist as for example, in drug trials you can’t get access to medicine without being in a treatment group
What does ITT stand for?
Intent to treat - effect of being offered treatment
What is Local Average Treatment Effect (LATE)?
Only applies to some of the population.
How do we identify the compliance rate?
- Record compliance
- Compliance: pi(c) = %c in treatment = %c in control
What is the formula for CACE (effect of treatment)?
CACE = ITT/pi(c)
