Kernel regression 2026-10-14
Kernel regression estimates a regression function using localized kernel weights rather than a fixed finite-dimensional functional form. The Nadaraya–Watson estimator is the local-constant version; local polynomial regression improves its local approximation by fitting a polynomial.
Nadaraya–Watson estimator Created 2026-09-28 Updated 2026-10-14
This local-constant estimator is one particular kernel regression method.
The Nadaraya–Watson estimator is the degree-zero local polynomial estimate
At a support boundary it generally has first-order bias because it reproduces constants but not linear functions.