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28 results on '"Walschaerts, Marie"'

2. Stable variable selection for right censored data: comparison of methods

Author

Walschaerts, Marie, Leconte, Eve, and Besse, Philippe

Subjects
Statistics - Applications
Abstract

The instability in the selection of models is a major concern with data sets containing a large number of covariates. This paper deals with variable selection methodology in the case of high-dimensional problems where the response variable can be right censored. We focuse on new stable variable selection methods based on bootstrap for two methodologies: the Cox proportional hazard model and survival trees. As far as the Cox model is concerned, we investigate the bootstrapping applied to two variable selection techniques: the stepwise algorithm based on the AIC criterion and the L1-penalization of Lasso. Regarding survival trees, we review two methodologies: the bootstrap node-level stabilization and random survival forests. We apply these different approaches to two real data sets. We compare the methods on the prediction error rate based on the Harrell concordance index and the relevance of the interpretation of the corresponding selected models. The aim is to find a compromise between a good prediction performance and ease to interpretation for clinicians. Results suggest that in the case of a small number of individuals, a bootstrapping adapted to L1-penalization in the Cox model or a bootstrap node-level stabilization in survival trees give a good alternative to the random survival forest methodology, known to give the smallest prediction error rate but difficult to interprete by non-statisticians. In a clinical perspective, the complementarity between the methods based on the Cox model and those based on survival trees would permit to built reliable models easy to interprete by the clinician., Comment: nombre de pages : 29 nombre de tableaux : 2 nombre de figures : 9

Published
2012

13. Sperm aneuploidy after testicular cancer treatment: data from a prospective multicenter study performed within the French Centre d’Étude et de Conservation des Oeufs et du Sperme network

Author

Rives, Nathalie, primary, Walschaerts, Marie, additional, Setif, Véronique, additional, Hennebicq, Sylvianne, additional, Saias, Jacqueline, additional, Brugnon, Florence, additional, Auger, Jacques, additional, Berthaut, Isabelle, additional, Szerman, Ethel, additional, Daudin, Myriam, additional, and Bujan, Louis, additional

Published
2017
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14. Impact of Hodgkin or non-Hodgkin lymphoma and their treatments on sperm aneuploidy: a prospective study by the French CECOS network

Author

Martinez, Guillaume, primary, Walschaerts, Marie, additional, Le Mitouard, Marine, additional, Borye, Remi, additional, Thomas, Claire, additional, Auger, Jacques, additional, Berthaut, Isabelle, additional, Brugnon, Florence, additional, Daudin, Myriam, additional, Moinard, Nathalie, additional, Ravel, Célia, additional, Saias, Jacqueline, additional, Szerman, Ethel, additional, Rives, Nathalie, additional, Hennebicq, Sylviane, additional, and Bujan, Louis, additional

Published
2017
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16. Stable variable selection for right censored data: comparison of methods

Author

Besse, Philippe, Leconte, Eve, and Walschaerts, Marie

Subjects
B- ECONOMIE ET FINANCE
Abstract

The instability in the selection of models is a major concern with data sets containing a large number of covariates. This paper deals with variable selection methodology in the case of high-dimensional problems where the response variable can be right censored. We focuse on new stable variable selection methods based on bootstrap for two different methodologies commonly used in survival analysis: the Cox proportional hazard model and survival trees. As far as the Cox model is concerned, we investigate the bootstrapping applied to two variable selection techniques: the stepwise algorithm based on the AIC criterion and the L1-penalization of Lasso. Regarding survival trees, we review two methodologies: the bootstrap node-level stabilization and random survival forests. We apply these different approaches to two real data sets, a classical breast cancer data set and an original infertility data set. We compare the methods on two criteria: the prediction error rate based on the Harrell concordance index and the relevance of the interpretation of the corresponding selected models, focusing on the original infertility data set. The aim is to find a compromise between a good prediction performance and ease to interpretation for clinicians. Results suggest that in the case of a small number of individuals, a bootstrapping adapted to L1-penalization in the Cox model or a bootstrap node-level stabilization in survival trees give a good alternative to the random survival forest methodology, known to give the smallest prediction error rate but difficult to interprete by non-statisticians. In a clinical perspective, the complementarity between the methods based on the Cox model and those based on survival trees would permit to built reliable models easy to interprete by the clinician.

Published
2012

17. Stable variable selection for right censored data: comparison of methods

Author

Besse, Philippe, Leconte, Eve, Walschaerts, Marie, Groupe de recherche en fertilité humaine ( GRFH), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT), Groupe de recherche en économie mathématique et quantitative (GREMAQ), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de la Recherche Agronomique (INRA)-École des hautes études en sciences sociales (EHESS)-Centre National de la Recherche Scientifique (CNRS), Institut de Mathématiques de Toulouse UMR5219 (IMT), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Centre National de la Recherche Scientifique (CNRS)-École des hautes études en sciences sociales (EHESS)-Institut National de la Recherche Agronomique (INRA)-Université Toulouse 1 Capitole (UT1), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-École des hautes études en sciences sociales (EHESS)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)

Subjects
FOS: Computer and information sciences, survival trees, [STAT.AP]Statistics [stat]/Applications [stat.AP], survival random forests, Cox model, censored data, Applications (stat.AP), Lasso, variable selection, bootstrap, Statistics - Applications
Abstract

The instability in the selection of models is a major concern with data sets containing a large number of covariates. This paper deals with variable selection methodology in the case of high-dimensional problems where the response variable can be right censored. We focuse on new stable variable selection methods based on bootstrap for two methodologies: the Cox proportional hazard model and survival trees. As far as the Cox model is concerned, we investigate the bootstrapping applied to two variable selection techniques: the stepwise algorithm based on the AIC criterion and the L1-penalization of Lasso. Regarding survival trees, we review two methodologies: the bootstrap node-level stabilization and random survival forests. We apply these different approaches to two real data sets. We compare the methods on the prediction error rate based on the Harrell concordance index and the relevance of the interpretation of the corresponding selected models. The aim is to find a compromise between a good prediction performance and ease to interpretation for clinicians. Results suggest that in the case of a small number of individuals, a bootstrapping adapted to L1-penalization in the Cox model or a bootstrap node-level stabilization in survival trees give a good alternative to the random survival forest methodology, known to give the smallest prediction error rate but difficult to interprete by non-statisticians. In a clinical perspective, the complementarity between the methods based on the Cox model and those based on survival trees would permit to built reliable models easy to interprete by the clinician., nombre de pages : 29 nombre de tableaux : 2 nombre de figures : 9

Published
2011

18. Sperm cryopreservation in adolescents and young adults with cancer: results of the French national sperm banking network (CECOS)

Author

Daudin, Myriam, primary, Rives, Nathalie, additional, Walschaerts, Marie, additional, Drouineaud, Véronique, additional, Szerman, Ethel, additional, Koscinski, Isabelle, additional, Eustache, Florence, additional, Saïas-Magnan, Jacqueline, additional, Papaxanthos-Roche, Aline, additional, Cabry-Goubet, Rosalie, additional, Brugnon, Florence, additional, Le Lannou, Dominique, additional, Barthélémy, Claire, additional, Rigot, Jean-Marc, additional, Fréour, Thomas, additional, Berthaut, Isabelle, additional, Giscard d'Estaing, Sandrine, additional, Touati, Françoise, additional, Mélin-Blocquaux, Marie-Claude, additional, Blagosklonov, Oxana, additional, Thomas, Claire, additional, Benhamed, Mohamed, additional, Schmitt, Françoise, additional, Kunstmann, Jean-Marie, additional, Thonneau, Patrick, additional, and Bujan, Louis, additional

Published
2015
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19. Impact of lymphoma treatments on spermatogenesis and sperm deoxyribonucleic acid: a multicenter prospective study from the CECOS network

Author

Bujan, Louis, primary, Walschaerts, Marie, additional, Brugnon, Florence, additional, Daudin, Myriam, additional, Berthaut, Isabelle, additional, Auger, Jacques, additional, Saias, Jacqueline, additional, Szerman, Ethel, additional, Moinard, Nathalie, additional, Rives, Nathalie, additional, and Hennebicq, Sylvianne, additional

Published
2014
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28. Sperm cryopreservation: recent and marked increase in use for testicular cancer compared with Hodgkin disease.

Author

Walschaerts M, Muller A, Daudin M, Hennebicq S, Huyghe E, and Thonneau P

Subjects
Cryopreservation statistics & numerical data, Humans, Male, Poisson Distribution, Regression Analysis, Cryopreservation methods, Hodgkin Disease physiopathology, Semen Preservation methods, Semen Preservation statistics & numerical data, Testicular Neoplasms physiopathology
Published
2007
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