Chang, Ziqing; Xue, Liugen; Zhu, Lixing - In: Journal of Multivariate Analysis 101 (2010) 8, pp. 1898-1901
In this note, we revisit the single-index model with heteroscedastic error, and recommend an estimating equation method in terms of transferring restricted least squares to unrestricted least squares: the estimator of the index parameter is asymptotically more efficient than existing estimators...