Plug-in bandwidth minimising the asymptotic mean squared error of the local linear regression-discontinuity estimator (Imbens and Kalyanaraman 2009, Sec. 4.4). Step 1 forms a pilot Silverman window and estimates the running-variable density and the conditional variance at the cutoff; step 2 fits a global cubic to get the third derivative and from it side-specific pilot windows, then a quadratic on each side for the second derivatives; step 3 combines them with the regularisation terms of their eq. (4.10).
Value
A list with estimate (the bandwidth) and the full
set of intermediate quantities: h1, f_hat,
sigma2, n_left_h1, n_right_h1,
mean_left_h1, mean_right_h1, m3,
h2_left, h2_right, m2_left, m2_right,
n2_left, n2_right, n2_left_full,
n2_right_full, r_left, r_right,
h_unregularized, kernel_constant, n,
method.
