Source: Ann. Statist. Volume 38, Number 1
(2010), 246-274.
In this paper, we study the estimation for a partial-linear single-index model. A two-stage estimation procedure is proposed to estimate the link function for the single index and the parameters in the single index, as well as the parameters in the linear component of the model. Asymptotic normality is established for both parametric components. For the index, a constrained estimating equation leads to an asymptotically more efficient estimator than existing estimators in the sense that it is of a smaller limiting variance. The estimator of the nonparametric link function achieves optimal convergence rates, and the structural error variance is obtained. In addition, the results facilitate the construction of confidence regions and hypothesis testing for the unknown parameters. A simulation study is performed and an application to a real dataset is illustrated. The extension to multiple indices is briefly sketched.
References
Arnold, S. F. (1981). The Theory of Linear Models and Multivariate Analysis. Wiley, New York.
Mathematical Reviews (MathSciNet):
MR606011
Bhattacharya, P. K. and Zhao, P.-L. (1997). Semiparametric inference in a partial linear model. Ann. Statist. 25 244–262.
Carroll, R. J., Fan, J., Gijbels, I. and Wand, M. P. (1997). Generalized partially linear single-index models. J. Amer. Statist. Assoc. 92 477–489.
Chen, C.-H. and Li, K.-C. (1998). Can SIR be as popular as multiple linear regression. Statist. Sinica 8 289–316.
Chen, H. (1988). Convergence rates for parametric components in a partly linear model. Ann. Statist. 16 136–141.
Mathematical Reviews (MathSciNet):
MR924861
Chen, H. and Shiau, J.-J. H. (1994). Data-driven efficient estimators for a partially linear model. Ann. Statist. 22 211–237.
Chiou, J. M. and Müller, H. G. (1998). Quasi-likelihood regression with unknown link and variance functions. J. Amer. Statist. Assoc. 93 1376–1387.
Cook, R. D. (1998). Regression Graphics: Ideas for Studying Regressions Through Graphics. Wiley, New York.
Cook, R. D. (2007). Fisher lecture: Dimension reduction in regression 1, 2. Statist. Sci. 22 1–26.
Cook, R. D. and Li, B. (2002). Dimension reduction for the conditional mean in regression. Ann. Statist. 30 455–474.
Cook, R. D. and Wiseberg, S. (1991). Comment on “Sliced inverse regression for dimension reduction,” by K. C. Li. J. Amer. Statist. Assoc. 86 328–332.
Craven, P. and Wahba, G. (1979). Smoothing and noisy data with spline functions: Estimating the correct degree of smoothing by the method of generalized cross-validation. Numer. Math. 31 377–403.
Mathematical Reviews (MathSciNet):
MR516581
Doksum, K. and Samarov, A. (1995). Nonparametric estimation of global functionals and a measure of the explanatory power of covariates in regression. Ann. Statist. 23 1443–1473.
Fan, J. and Gijbels, I. (1996). Local Polynomial Modeling and Its Applications. Chapman and Hall, London.
Friedman, J. H. and Stuetzle, W. (1981). Projection pursuit regression. J. Amer. Statist. Assoc. 76 817–823.
Mathematical Reviews (MathSciNet):
MR650892
Gentle, J. E. (1998). Numerical Linear Algebra for Applications in Statistics. Springer, Berlin.
Hall, P. (1989). On projection pursuit regression. Ann. Statist. 17 573–588.
Mathematical Reviews (MathSciNet):
MR994251
Härdle, W., Hall, P. and Ichimura, H. (1993). Optimal smoothing in single-index models. Ann. Statist. 21 157–178.
Härdle, W., Gao, J. and Liang, H. (2000). Partially Linear Models. Springer, New York.
Harrison, D. and Rubinfeld, D. (1978). Hedonic housing pries and the demand for clean air. Journal of Environmental Economics and Management 5 81–102.
Heckman, N. (1986). Spline smoothing in a partly linear model. J. Roy. Statist. Soc. Ser. A 48 244–248.
Mathematical Reviews (MathSciNet):
MR868002
Hristache, M., Juditsky, A. and Spokoiny, V. (2001). Direct estimation of the index coefficient in a single-index model. Ann. Statist. 29 595–623.
Hsing, T. and Carroll, R. J. (1992). An asymptotic theory for sliced inverse regression. Ann. Statist. 20 1040–1061.
Li, B., Wen, S. Q. and Zhu, L. X. (2008). On a projective resampling method for dimension reduction with multivariate responses. J. Amer. Statist. Assoc. 106 1177–1186.
Li, K. C. (1991). Sliced inverse regression for dimension reduction (with discussion). J. Amer. Statist. Assoc. 86 316–342.
Li, K. C. (1992). On principal Hessian directions for data visualization and dimension reduction: Another application of Stein’s lemma. J. Amer. Statist. Assoc. 87 1025–1039.
Li, K. C., Aragon, Y., Shedden, K. and Agnan, C. T. (2003). Dimension reduction for multivariate response data. J. Amer. Statist. Assoc. 98 99–109.
Li, Y. X. and Zhu, L. X. (2007). Asymptotics for sliced average variance estimation. Ann. Statist. 35 41–69.
Pollard, D. (1984). Convergence of Stochastic Processes. Springer, New York.
Mathematical Reviews (MathSciNet):
MR762984
Rice, J. (1986). Convergence rates for partially splined models. Statist. Probab. Lett. 4 203–208.
Mathematical Reviews (MathSciNet):
MR848718
Ruppert, D., Wand, M. P. and Carroll, R. J. (2003). Semiparametric Regression. Cambridge Univ. Press, New York.
Speckman, P. (1988). Kernel smoothing in partial linear models. J. Roy. Statist. Soc. Ser. B 50 413–434.
Mathematical Reviews (MathSciNet):
MR970977
Stoker, T. M. (1986). Consistent estimation of scaled coefficients. Econometrica 54 1461–1481.
Mathematical Reviews (MathSciNet):
MR868152
Stute, W. and Zhu, L. X. (2005). Nonparametric checks for single-index models. Ann. Statist. 33 1048–1083.
Wang, J. L., Xue, L. G., Zhu, L. X. and Chong, Y. S. (2009). Estimation for a partial-linear single index model. Available at arXiv:0905.2042.
Weisberg, S. and Welsh, A. H. (1994). Adapting for the missing linear link. Ann. Statist. 22 1674–1700.
Welsh, A. H. (1989). On M-processes and M-estimation. Ann. Statist. 17 337–361. [Correction (1990) 18 1500.]
Mathematical Reviews (MathSciNet):
MR981455
Xia, Y. and Härdle, W. (2006). Semi-parametric estimation of partially linear single-index models. J. Multivariate Anal. 97 1162–1184.
Xia, Y., Tong, H., Li, W. K. and Zhu, L. X. (2002). An adaptive estimation of dimension reduction space. J. Roy. Statist. Soc. Ser. B 64 363–410.
Xia, Y. (2006). Asymptotic distributions for two estimators of the single-index model. Econometric Theory 22 1112–1137.
Yin, X. and Cool, R. D. (2002). Dimension reduction for the conditional k-th moment in regression. J. Roy. Statist. Soc. Ser. B 64 159–175.
Yu, Y. and Ruppert, D. (2002). Penalized spline estimation for partially linear single-index models. J. Amer. Statist. Assoc. 97 1042–1054.
Zhu, L. X. and Ng, K. W. (1995). Asymptotics for sliced inverse regression. Statist. Sinica 5 727–736.
Zhu, L. X. and Ng, K. W. (2003). Checking the adequacy of a partial linear model. Statist. Sinica 13 763–781.
Zhu, L. X. and Xue, L. G. (2006). Empirical likelihood confidence regions in a partially linear single-index model. J. Roy. Statist. Soc. Ser. B 68 549–570.