Highlights -- Dialogue behind the scenes .............................. Michelle Liou 1059 Editorial -- Innovations in dealing with missing data or missing reports ............ ..................................................................... Xiao-Li Meng 1061 Local quasi-likelihood estimation with data missing at random ....................... ........................... Jianwei Chen, Jianqing Fan, Kim-Hung Li and Haibo Zhou 1071 An empirical likelihood method in mixture models with incomplete classifications .... ........................................................ Song Xi Chen and Jing Qin 1101 Analysis of nonlinear structural equation models with nonignorable missing covariates and ordered categorical data ..................... Sik-Yum Lee and Nian-Sheng Tang 1117 Likelihood-based inference with nonignorable missing responses and covariates in models for discrete longitudinal data ... Amy L. Stubbendick and Joseph G. Ibrahim 1143 Efficiencies of methods dealing with missing covariates in regression analysis ...... ............................................... Cuiling Wang AND Myunghee Cho Paik 1169 A revisit of semiparametric regression models with missing data ..................... .......................................................... Menggang Yu and Bin Nan 1193 Inferences in censored cost regression models with empirical likelihood ............. ........................................ X. H. Zhou, G. S. Qin, H.Z. Lin and G. Li 1213 Robust nonparametric frontier estimators: qualitative robustness and influence function .................................... Abdelaati Daouia and Anne Ruiz-Gazen 1233 Long-memory wavelet models ............................................. Nan-Jung Hsu 1255 A note on the lasso and related procedures in model selection ....................... ............................................. Chenlei Leng, Yi Lin and Grace Wahba 1273 Connections among different criteria for asymmetrical fractional factorial designs .. ................................ Min-Qian Liu, Kai-Tai Fang and Fred J. Hickernell 1285 Unique optimal partitions of distributions and connections to hazard rates and stochastic ordering .............................. David Mease and Vijayan N. Nair 1299 On the estimation and testing of time varying constraints in econometric models ..... .................................. Susan Orbe, Eva Ferreira and Juan Rodriguez-Poo 1313 Strong limit theorems on model selection in generalized linear regression with binomial responses ...................................... Guoqi Qian and Yuehua Wu 1335 Modeling the subdistribution of a competing risk .................................... .......................... Liuquan Sun, Jingxia Liu, Jianguo Sun and Mei-Jie Zhang 1367 Two-way heteroscedastic ANOVA when the number of levels is large .................... .................................................. Lan Wang and Michael G. Akritas 1387 Exact convergence rate and leading term in the Central Limit Theorem for U-statistics .................................................. Qiying Wang and Neville C Weber 1409 Additive coefficient modeling via polynomial spline ......... Lan Xue and Lijian Yang 1423 Errata .............................................................................. 14472006 Statistica Sinica ISSN 1017-0405