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Webinar Series in Applied Quantitative Analysis - Updated
Date | Topic |
�February 29�March 7 | Session One�Potential Outcomes and Omitted Variable Bias I (Theory) �Potential Outcomes and Omitted Variable Bias II (Application) |
�March 21�March 28 | Session Two�Difference-in-differences I (Theory)�Difference-in-differences II (Application) |
�April 25�May 2 | Session Three�Power analysis, clustering and sample size calculations I (Theory)�Power analysis, clustering and sample size calculations II (Application) |
May 23�May 30 | Session Four�Propensity score matching (Theory)�Propensity score matching (Application) |
�June 20�June 27 | Session Five�Fixed-effects I (Theory)�Fixed-effects II (Application) |
�July 25�August 1 | Session Six�Instrumental variables I (Theory)�Instrumental Variables II (Application) |
August 22 August 29 | Session Seven�Lagged dependent variables and the Arellano-Bond Estimator I (Theory)�Lagged dependent variables and the Arellano-Bond Estimator II (Application) |
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Dynamic Panel Data Estimation II - Application
Ashu Handa
Institute Fellow – AIR
Kenan Eminent Professor of Public Policy – UNC-CH
August 29, 2024
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Recap of the main problem and the Blundell-Bond (1998) solution
Hit = β0 + β1(Hit-1) + β2(Xit) + β3(Xht) + (εit + µi)
Current period (t) height depends on lagged height (t-1)
Truly random error: not correlated
with Xs nor Hit-1
Health endowment of child: fixed over
time and correlated with Hi in each period
We have an endogeneity problem: Hit-1 is correlated with the error term!
Hit = β0 + β1(Hit-1) + β2(Xit) + β3(Xht) + (εit + µi)
We can solve this using IV. Instruments must satisfy two criteria
The Blundell-Bond (1998) system estimator
Hit = β0 + β1(Hit-1) + β2(Xit) + β3(Xht) + (εit + µi) (1)
Use (Hit-1 – Hit-2) as an instrument for Hit-1
Use Hit-2 as the instrument for (Hit-1 – Hit-2)
ΔHit = β1(ΔHit-1) + β2(ΔXit) + β3(ΔXht) + (Δεit) (3)
Levels equation with a lagged
differenced instrument
Differenced equation with a lagged
levels instrument
Hit = β0 + β1(Hit-1) + β2(Xit) + β3(Xht) + (εit + µi)
Weak instrument problem identified by Blundell-Bond
Differenced equation with
two period lagged instrument in levels
System estimator
System estimator
Other exogenous variables can serve as instruments. In this case we have used prices and long-run wealth.
xtdpd htz l.htz X1 Prices, dgmmiv(htz) lgmmiv(htz) div(Prices) liv(Lprices) artests(1) two vce(robust)
STATA command
‘dynamic panel data’ estimation
Dependent variable: htz�Lagged dependent variable as predictor: l.htz�(lag operator in STATA, must tsset the data)
Other exogenous variables
in the model
xtdpd htz l.htz X1 Prices, dgmmiv(htz) lgmmiv(htz) div(Prices) liv(Lprices) artests(1) two vce(robust)
STATA command
‘dynamic panel data’ estimation
‘GMM-style’ IV for the differenced equation
[This is the lagged dependent variable]
[STATA knows that this must be lagged two periods]
‘GMM style’ IV for the levels equation�[This is the lagged dependent variable]
[STATA knows this must be differenced]
xtdpd htz l.htz X1 Prices, dgmmiv(htz) lgmmiv(htz) div(Prices) liv(Lprices) artests(1) two vce(robust)
STATA command
‘dynamic panel data’ estimation
Other potential instruments for the differenced equation
They will be in levels or lagged levels, you must create these by hand
Other potential instruments for the levels equation
They will be in lags or lag differences, you must
create these by hand
xtdpd htz l.htz X1 Prices, dgmmiv(htz) lgmmiv(htz) div(Prices) liv(Lprices) artests(1) two vce(robust)
STATA command
‘dynamic panel data’ estimation
Other options, read about them by typing ‘help xtdpd’�I wont spend much time on them