Using `rdrobust` (Regression Discontinuity)

In this exercise you will use the rdrobust package for data-driven bandwidth selection and then check how sensitive the estimate is to bandwidth choice — the RDD equivalent of the specification charts from Week 10.

Run rdrobust fires10km v_pop, c(0) and note the conventional estimate, the bias-corrected estimate, and the optimal bandwidth selected.

1. What bandwidth does rdrobust select by default? How many observations fall within that bandwidth?

Now check bandwidth sensitivity. Loop over a set of bandwidths (25, 50, 75, 100, 150, 200) and store the conventional estimate and confidence interval at each bandwidth. Use the code below as a template:

* bandwidth sensitivity
	matrix			bw_results = J(6, 4, .)
	local			bandwidths 25 50 75 100 150 200
	local			row = 1

	foreach bw of local bandwidths {
		rdrobust	fires10km v_pop, c(0) h(`bw')
		matrix		bw_results[`row', 1] = `bw'
		matrix		bw_results[`row', 2] = e(tau_cl)
		matrix		bw_results[`row', 3] = e(ci_l_cl)
		matrix		bw_results[`row', 4] = e(ci_r_cl)
		local		++row
	}

Convert the matrix to a dataset and create a coefplot-style graph showing the point estimate ± 95% CI at each bandwidth. Add a horizontal reference line at zero.

* convert matrix to dataset for plotting
	preserve
	clear
	svmat           bw_results
	rename         (bw_results1 bw_results2 bw_results3 ///
	                   bw_results4) (bandwidth estimate ///
                       ci_lo ci_hi)

	twoway         (rcap ci_lo ci_hi bandwidth, lcolor(navy)) ///
                       (scatter estimate bandwidth, ///
                       mcolor(navy) msymbol(circle)), ///
                       yline(0, lcolor(maroon) lpattern(dash)) ///
                       ytitle("RD Estimate") ///
                       xtitle("Bandwidth") ///
                       legend(off) ///
                       graphregion(color(white))
	graph export	"$answ/14-rdd-bw.png", replace
	restore

2. Export the figure and import it into your Overleaf document.

3. Is the fire-count estimate stable as you widen the bandwidth, or does it change substantially?