Econometrics
Regression discontinuity design: Example
Keisuke Kawata
IDEC
Question
True of false: you should suppose pure-random sampling data.
1. To obtain unbiased estimator by using RDD, discontinuous jump of treatment is needed.
2. To obtain unbiased estimator by using RDD, discontinuous jump of outcomes is needed.
3. To obtain unbiased estimator by using RDD, the running variable must not have direct impacts on outcome.
Graphical image of IV
Explained variable Explanation
variables
Error term Instrumental
variables
Instrument relevance
Instrument exogeneity
Graphical image of RD
Explained variable Explanation
variables
Error term Running
variables
“ all ha ge of ru i g aria le must have no effects.
1
stexample: Angrist and Lavy ( 99 QJE )
Purpose: Effect of class size on education achievement
Data: Survey for students (4th and 5th graders) in Israeli elementary schools. Outcomes: Test score of mathematics and reading.
Treatments: Class size. Empirical strategy:
Source of bias: Endogenous class asignment
⇒ The allocation of students for class are determined by teachers. lo a hie e e t stude ts ay e allo ated to s all size lass.
Fuzzy RD
I stru e tal aria le: predi ted lass size
• The maximum class size is 40 (Maimonides rule).
⇒ Predi ted u er of lass are
⇒ predi ted lass size= �
� �
Total number of student in a school Predicted number of class
1~40 1
41~80 2
81~121 3
Graphically check of relevance: 4
thgrade
Graphically check of relevance: 5
thgrade
Estimation model
• 2SLS estimation. 1st stage:
�� �� � � � �� �� �, ��
= + ∗ � �� �� + ∗ �
2nd stage:
� � �� �� �, �� = + ∗ �� �� + ∗ �
Standard IV approach: using whole sample
RDD approach: Using samples with +5/-5 enrollments at discontinuous jump.
OLS results
Thumb rule for significance: If the (absolute) value of estimated coefficient is more than twice for estimated standard deviation, this estimator is significant with 5%.
IV and RDD results
IV and RDD results
2
ndexample: Political resource curse?
Resource : Foreign aid, budget transfer, and revenue from natural resource.
→may bring good impacts. ⇔ may also have bad impacts. e.g.,) Resource cause: Dutch disease hypothesis
Resource
Currency exchange rate ↑ Exporting industry ↓ Economy
2
ndexample: Political resource curse?
Political resource curse: Distri utio of resour e ay ause politi al i sta ility and corruption.
Resource
Bad political outcome: instability, corruption
Economy
Crost et al (14 AER)
Purpose: Effect of development program on civil conflict. Data: Municipality level data in Philippines.
Outcomes: The number of casualties by civil conflict. Treatments: Eligibility of a development program.
Empirical strategy: RDD(running variable: Relative Poverty rank)
KALAHI-CIDSS program
Community-driven development program: to enhance local infrastructure, governance, participation, and social cohesion.
Target: poor u i ipalities. Process:
Check eligibility Social preparation phase
To participate the program, set up the required institutional infrastructure (e.g., village meetings)
Program phase
Receiving large grand (6000$ per village) to construct local public goods.
Targeting area
Empirical strategy
•Eligibility is determined by the poverty level of municipalities.
•Authors estimate the relative poverty level; if the level is less than zero, the municipal can participate the program.
Relationship between poverty level and program
Check the assumption
Empirical strategy: outcome
• Outcome is the number of casualties.
Empirical strategy
• Parametric model
� = + � � + � + � + � � + � � + + + �
where � is outcome in municipality i in province p in phase t, � is poverty level, and � is dummy: =1 if � ≤ 0 and dummy: =0 if � > 0
• Nonparametric approach is also used.
Note: Even if a municipality has eligibility, they may not join program.
⇒If interest is the effect of program, � should be used as IV.
Ho e er, authors’ i terest is the i pa ts of eligi ility , there y esti ati g i pa ts of eligibility.
Check the assumption
Main results
Main results
Final examination
• Date: July 30, 14:35~ (1 hour), Place: 206
• After reading assignment paper, summarizing paper.
• No book and course material examination ⇒ You can bring just writing implement (and your brain).
Homework
Make a summary of following paper;
Alesina, A., Giuliano, P., & Nunn, N. (2011). Fertility and the Plough. American Economic Review, 101(3), 499-503.
⇒I will collect summary seat in 28, July.
Reference
Angrist, J. D., & Lavy, V. (1999). Using Maimonides' Rule to Estimate the Effect of Class Size on Scholastic Achievement. The Quarterly Journal of Economics, 114(2), 533-575.
Crost, B., Felter, J., & Johnston, P. (2014). Aid under fire: Development projects and civil conflict. The American Economic Review, 104(6), 1833-1856.