Fuzzy RDD (Regression Discontinuity)
Now we estimate the fuzzy RD — the causal effect of actually receiving a road on fire activity and air pollution. Following the IV logic from Week 13, we use the population threshold t as an instrument for receivedroad.
- Run the fuzzy RD for fires (
fires10km) usingivreghdfeand instrumenting forreceivedroadwitht. - Include as exogenous left-hand-side variables
left rightand the baseline controls. - Absorb district-threshold (
dist_thresh_id) and year (year) fixed effects, and clustering standard errors at thevillage_idlevel. - Use triangular kernel weights
[aw = kernel_tri_ik]. - Store results as
iv_fires. - Finally, calculate the control group mean for fires within the effective sample (
if e(sample) & t == 0) and store it as a scalar calleddepvarmean. - Run the same specification for
pm25(replacefires10kmwithpm25andfires2001_10kmwithpm25_bl2001as the baseline control). Store asiv_pm. and again calculate the control group mean for pm25 within the effective sample and store it asdepvarmean.
1. Export a four-column table. Make sure you still have the reduced-form estimates from Exercise 2 (rf2) and the first-stage estimate from Exercise 4 (fs) stored.
* four-column table
esttab fs rf2 iv_fires iv_pm ///
using "$answ/14-rdd-fuzzy.tex", replace ///
b(3) se(3) ///
keep(t receivedroad) ///
coeflabels(t "Above threshold" ///
receivedroad "Road built") ///
star(* 0.10 ** 0.05 *** 0.01) ///
mtitles("Road" "Fires" "Fires" "PM 2.5") ///
stats(N depvarmean, ///
labels("Observations" ///
"Control group mean") ///
fmt(0 2)) ///
noobs booktabs nonum collabels(none) ///
nobaselevels nogaps fragment label ///
prehead("\begin{tabular}{l*{4}{c}} " ///
"\\[-1.8ex]\hline \hline \\[-1.8ex] " ///
"& \multicolumn{2}{c}{1st Stage} " ///
"& \multicolumn{2}{c}{Fuzzy RD (IV)}" ///
" \\ \midrule") ///
postfoot("\hline \hline \\[-1.8ex] " ///
"\multicolumn{5}{p{\linewidth}}{\small " ///
"\noindent \textit{Note}: All models " ///
"include baseline controls, " ///
"district-threshold and year FE, and " ///
"triangular kernel weights. Std.\ errors " ///
"clustered at village level. " ///
"* p$<$0.10, ** p$<$0.05, " ///
"*** p$<$0.01.} " ///
"\end{tabular}")
2. Does road construction increase or decrease air pollution? Is this consistent with the direction of the fire effect?