title: Multiple Imputation based Clustering Validation (MIV) for Big Longitudinal Trial Data with Missing Values in eHealth.
abstract: Web-delivered trials are an important component in eHealth services. These trials, mostly behavior-based, generate big heterogeneous data that are longitudinal, high dimensional with missing values. Unsupervised learning methods have been widely applied in this area, however, validating the optimal number of clusters has been challenging. Built upon our multiple imputation (MI) based fuzzy clustering, MIfuzzy, we proposed a new multiple imputation based validation (MIV) framework and corresponding MIV algorithms for clustering big longitudinal eHealth data with missing values, more generally for fuzzy-logic based clustering methods. Specifically, we detect the optimal number of clusters by auto-searching and -synthesizing a suite of MI-based validation methods and indices, including conventional (bootstrap or cross-validation based) and emerging (modularity-based) validation indices for general clustering methods as well as the specific one (Xie and Beni) for fuzzy clustering. The MIV performance was demonstrated on a big longitudinal dataset from a real web-delivered trial and using simulation. The results indicate MI-based Xie and Beni index for fuzzy-clustering are more appropriate for detecting the optimal number of clusters for such complex data. The MIV concept and algorithms could be easily adapted to different types of clustering that could process big incomplete longitudinal trial data in eHealth services.
authors.affiliation: Department of Quantitative Health Science, University of Massachusetts Medical School, Worcester, MA, 01655, USA.
authors.forename: Zhaoyang
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Quantitative Health Science, University of Massachusetts Medical School, Worcester, MA, 01655, USA. hua.fang@umassmed.edu.
authors.forename: Hua
authors.initials: H
authors.lastname: Fang
authors.affiliation: Department of Electrical and Computer Engineering, University of Massachusetts Dartmouth, North Dartmouth, MA, 02747, USA.
authors.forename: Honggang
authors.initials: H
authors.lastname: Wang
mesh_terms: D000465:Algorithms; D002986:Clinical Trials as Topic; D016000:Cluster Analysis; D003627:Data Interpretation, Statistical; D017143:Fuzzy Logic; D006801:Humans; D008137:Longitudinal Studies; D017216:Telemedicine
keywords: Big data; Fuzzy clustering; Longitudinal trial; Missing data; Multiple imputation; Validation