Local polynomial regression is widely used for nonparametric regression. However, the efficiency of least squares (LS) based methods is adversely affected by outlying observations and heavy tailed distributions. On the other hand, the least absolute deviation (LAD) estimator is more robust, but...

This work is concerned with robust estimation in a semiparametric varying-coefficient partially linear model when the underlying error distribution deviates from a normal distribution. We develop a robust estimator by minimizing a locally Walsh-average-based loss function. We show theoretically...

This paper is concerned with estimating the coefficients in single-index models. We develop a robust estimator, which combines the ideas of rank-based regression inference and outer product of gradients. Both asymptotic and numerical results show that the proposed procedure has better...