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Exploratory analysis of longitudinal trials with staggered intervention times.

Chetwynd, Amanda G. and Diggle, Peter J. and Sousa, Ines (2005) Exploratory analysis of longitudinal trials with staggered intervention times. Biostatistics, 6 (3). pp. 479-485. ISSN 1468-4357

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Abstract

Longitudinal trials involving surgical interventions commonly have subject-specific intervention times, due to constraints on the availability of surgeons and operating theatres. Moreover, the intervention often effects a discontinuous change in the mean response. We propose a nonparametric estimator for the mean response profile of longitudinal data with staggered intervention times and a discontinuity at the times of intervention, as an exploratory tool to assist the formulation of a suitable parametric model. We use an adaptation of the standard generalized additive model algorithm for estimation, with smoothing constants chosen by a cross-validation criterion. We illustrate the method using longitudinal data from a trial to assess the effect of lung resection surgery in the treatment of emphysema patients.

Item Type: Article
Journal or Publication Title: Biostatistics
Additional Information: RAE_import_type : Journal article RAE_uoa_type : Statistics and Operational Research
Uncontrolled Keywords: Back-fitting algorithm ; Cross-validation ; Exploratory analysis ; Longitudinal trials ; Lung resection surgery ; Nonparametric estimator
Subjects: Q Science > QA Mathematics
Departments: Faculty of Science and Technology > Mathematics and Statistics
VC's Office
Faculty of Health and Medicine > Medicine
Faculty of Science and Technology > Lancaster Environment Centre
ID Code: 2408
Deposited By: ep_importer
Deposited On: 31 Mar 2008 16:35
Refereed?: Yes
Published?: Published
Last Modified: 26 Jul 2012 16:21
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/2408

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