• Title/Summary/Keyword: time-varying frailty

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Statistical Analysis of Recidivism Data Using Frailty Effect (프레일티를 이용한 재범 자료의 연구)

  • Kim, Yang-Jin
    • The Korean Journal of Applied Statistics
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    • v.23 no.4
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    • pp.715-724
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    • 2010
  • Recurrent event data occurs when a subject experience the event of interest several times and has been found in biomedical studies, sociology and engineering. Several diverse approaches have been applied to analyze the recurrent events (Cook and Lawless, 2007). In this study, we analyzed the YTOP(Young Traffic Offenders Program) dataset which consists of 192 drivers with conviction dates by speeding violation and traffic rule violation. We consider a subject-specific effect, frailty, to reflect the individual's driving behavior and extend to time-varying frailty effect. Another feature of this study is about the redefinition of risk set. During the study, subject may be under suspension and this period is regarded as non-risk period. Thus the risk variables are reformatted according to suspension and termination time.

Analysis of Recurrent Gap Time Data with a Binary Time-Varying Covariate

  • Kim, Yang-Jin
    • Communications for Statistical Applications and Methods
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    • v.21 no.5
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    • pp.387-393
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    • 2014
  • Recurrent gap times are analyzed with diverse methods under several assumptions such as a marginal model or a frailty model. Several resampling techniques have been recently suggested to estimate the covariate effect; however, these approaches can be applied with a time-fixed covariate. According to simulation results, these methods result in biased estimates for a time-varying covariate which is often observed in a longitudinal study. In this paper, we extend a resampling method by incorporating new weights and sampling scheme. Simulation studies are performed to compare the suggested method with previous resampling methods. The proposed method is applied to estimate the effect of an educational program on traffic conviction data where a program participation occurs in the middle of the study.