Mechanism for Missing Data Incorporated in Joint Modelling of Ordinal Responses
分析了两个临床不可分离的有序重复测量响应（如治疗效果和副作用程度）的联合建模问题，并纳入缺失机制，研究了非随机缺失模型与随机缺失模型的近似性，以及不同识别限制对多重插补的影响，提出了一种减少计算时间的数值近似方法。
Summary We analyse the problem of two clinically inseparable, repeatedly measured responses of ordinal type by also incorporating their missingness process. In our application these are the therapeutic effect and extent of side effects of fluvoxamine. In the case of a composite end point, the scientific questions addressed can be answered only when the responses are modelled jointly. As an extension of the methodology, several missingness not at random models were fitted to a set of observed data and shown to yield approximately the same result as their missingness at random counterparts, although it affects precision. In addition, the effect of various identifying restrictions on multiple imputation is investigated. An alternative numerical approximation method is suggested to reduce computational time.