CHAPTER 12 Regression Discontinuity Designs Flashcards
What is a regression discontinuity design?
A method to estimate causal effects when a treatment changes discontinuously at a known threshold.
What does regression discontinuity designs estimate?
A local average treatment effect for units right around the threshold where treatment changes.
In what situation is a regression discontinuity design appropriate?
When a treatment changes discontinuously at a known threshold.
What is the running variable in a regression discontinuity design?
A third variable that determines treatment assignment based on whether it is above or below a threshold.
What is the local average treatment effect (LATE)?
The average treatment effect for units with values of the running variable right at the threshold.
True or False: Regression discontinuity designs can provide unbiased causal estimates.
True.
What is an example of a situation where a regression discontinuity design might be used?
Estimating the effect of receiving a merit scholarship based on a strict scoring rule.
What is the naive approach in implementing an RD design?
Comparing mean outcomes for small ranges of the running variable on either side of the threshold.
What is a significant disadvantage of the naive approach?
It is likely to produce biased estimates due to correlation between the running variable and potential outcomes.
What is a local linear approach in regression discontinuity designs?
Running linear regressions of the outcome on the running variable separately on either side of the threshold.
What is the purpose of selecting a bandwidth in an RD design?
To balance the trade-off between reducing bias and improving precision.
What does the regression discontinuity design estimate when comparing groups just above and below the threshold?
The ‘jump’ or ‘discontinuity’ in the outcome as the running variable crosses the threshold.
What is the effect of using polynomial regressions in an RD design?
It accounts for possible non-linear relationships between the running variable and the outcome.
Fill in the blank: The regression discontinuity design is useful for estimating effects of government programs that change at known _______.
thresholds.
What is an important consideration when interpreting results from a regression discontinuity design?
The estimated effect is local and may not represent the overall average treatment effect in the population.
What is one common application of regression discontinuity designs?
Estimating the effects of government programs that are means-tested.
True or False: The local average treatment effect can differ from the overall average treatment effect.
True.
What is the significance of the threshold in a regression discontinuity design?
It determines which units receive the treatment and which do not.
What does it mean when we say the average treatment effect can differ at different values of the running variable?
The effect of treatment may vary for different groups near the threshold.
What is a common way that people implement RD designs?
Polynomial regressions that regress the outcome on treatment, the running variable, and higher-order polynomials.
What is a downside of using polynomial regressions in RD designs?
Data points far from the threshold can have a big effect on the estimated discontinuity.
What should researchers avoid when implementing an RD design?
Over-comparing and under-reporting.
What factors should decisions in RD designs depend on?
Substantive knowledge, beliefs about the relationship between running variable and outcome, and bias-precision trade-off.
What does it indicate if estimates are robust across different bandwidths in RD designs?
It lends additional credibility to the results.