Browsing by Author "Sinha, Debajyoti"

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    Bayesian analysis of survival data with missing censoring indicators
    (WILEY, 2021) Brownstein, Naomi C.; Bunn, Veronica; Castro, Luis M.; Sinha, Debajyoti
    In some large clinical studies, it may be impractical to perform the physical examination to every subject at his/her last monitoring time in order to diagnose the occurrence of the event of interest. This gives rise to survival data with missing censoring indicators where the probability of missing may depend on time of last monitoring and some covariates. We present a fully Bayesian semi-parametric method for such survival data to estimate regression parameters of the proportional hazards model of Cox. Theoretical investigation and simulation studies show that our method performs better than competing methods. We apply the proposed method to analyze the survival data with missing censoring indicators from the Orofacial Pain: Prospective Evaluation and Risk Assessment study.
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    Bregman divergence to generalize Bayesian influence measures for data analysis
    (2021) De Oliveira, Melaine C.; Castro, Luis M.; Dey, Dipak K.; Sinha, Debajyoti
    For existing Bayesian cross-validated measure of influence of each observation on the posterior distribution, this paper considers a generalization using the Bregman Divergence (BD). We investigate various practically useful and desirable properties of these BD based measures to demonstrate the superiority of these measures compared to existing Bayesian measures of influence and Bayesian residual based diagnostics. We provide a practical and easily comprehensible method for calibrating these BD based measures. Also, we show how to compute our BD based measure via Markov chain Monte Carlo (MCMC) samples from a single posterior based on the full data. Using a Bayesian meta-analysis of clinical trials, we illustrate how our new measures of influence of observations have more useful practical roles for data analysis than popular Bayesian residual analysis tools. (c) 2020 Elsevier B.V. All rights reserved.