首页 | 本学科首页   官方微博 | 高级检索  
     检索      


Efficiency of lattice conditional independence models for multinormal samples with non-monotone missing data
Authors:Lang Wu  Michael D Perlman
Institution:1. Department of Biostatistics , Harvard University , Boston, MA, 02115, USA;2. Department of Statistics , University of Washington , Seattle, WA, 98195, USA
Abstract:For multivariate normal data with non-monotone (i.e. arbitrary) missing data patterns, lattice conditional independence (LCI) models determined by the observed data patterns can be used to obtain closed-form MLEs (Andersson and Perlman, 1991, 1993). In this paper, three procedures — LCI models, the EM algorithm, and the complete-data method — are compared by means of a Monte Carlo experiment. When the LCI model is accepted by the LR test, the LCI estimate is more efficient than those based on the EM algorithm and the complete-data method. When the LCI model is not accepted, the LCI estimate may lose efficiency but still may be more efficient than the EM estimate if the observed data is sparse. When the LCI model appears too restrictive, it may be possible to obtain a less restrictive LCI model by.discarding only a small portion of the incomplete observations. LCI models appear to be especially useful when the observed data is sparse, even in cases where the suitability of the LCI model is uncertain.
Keywords:Closed-form MLE  EM algorithm  Model-restricted MLE  Simulation  Stein's loss
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号