Nonparametric estimation and U-statistics have emerged as vital tools in modern statistical analysis, offering robust alternatives to traditional parametric methods. Nonparametric techniques bypass ...

In this paper, we consider a nonparametric model with a time-varying regression function and locally stationary regressors. We are interested in the question whether the regression function has the ...

Journal of Business & Economic Statistics, Vol. 34, No. 4, Special Issue on Big Data (October 2016), pp. 661-672 (12 pages) Randomized controlled trials play an important role in how Internet ...