Journal ArticleDOI
A solution to the problem of separation in logistic regression
Georg Heinze,Michael Schemper +1 more
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A procedure by Firth originally developed to reduce the bias of maximum likelihood estimates is shown to provide an ideal solution to separation and produces finite parameter estimates by means of penalized maximum likelihood estimation.Abstract:
The phenomenon of separation or monotone likelihood is observed in the fitting process of a logistic model if the likelihood converges while at least one parameter estimate diverges to +/- infinity. Separation primarily occurs in small samples with several unbalanced and highly predictive risk factors. A procedure by Firth originally developed to reduce the bias of maximum likelihood estimates is shown to provide an ideal solution to separation. It produces finite parameter estimates by means of penalized maximum likelihood estimation. Corresponding Wald tests and confidence intervals are available but it is shown that penalized likelihood ratio tests and profile penalized likelihood confidence intervals are often preferable. The clear advantage of the procedure over previous options of analysis is impressively demonstrated by the statistical analysis of two cancer studies.read more
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Climate-Related Scenarios for Financial Stability Assessment: an Application to France
Thomas Allen,Stephane Dees,Jean Boissinot,Carlos Mateo Caicedo Graciano,Valérie Chouard,Laurent Clerc,Annabelle de Gaye,Antoine Devulder,Sébastien Diot,Noëmie Lisack,Fulvio Pegoraro,Marie Rabate,Romain Svartzman,Lucas Vernet +13 more
TL;DR: In this article, the authors propose an analytical framework to quantify the impacts of climate policy and transition narratives on economic and financial variables necessary for financial risk assessment, focusing on transition risks, the scenarios considered include unexpected increases in carbon prices and productivity shocks to reflect disorderly transition processes.
Journal ArticleDOI
Immunogenicity and Reactogenicity of 2009 Influenza A (H1N1) Inactivated Monovalent Non-Adjuvanted Vaccine in Elderly and Immunocompromised Patients
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Journal ArticleDOI
A rare missense variant of CASP7 is associated with familial late‐onset Alzheimer's disease
TL;DR: This study demonstrated that an enriched case design can strengthen genetic signals, thus allowing detection of associations that would otherwise be missed in a traditional case-control study.
Journal ArticleDOI
Hepatitis C in the general population of various ethnic origins living in the Netherlands: Should non-Western migrants be screened?
Anouk T. Urbanus,T.J.W. van de Laar,A van den Hoek,F. Zuure,Arjen G. C. L. Speksnijder,Gijs Baaten,Titia Heijman,Henrike J. Vriend,E L M Op de Coul,R. A. Coutinho,Maria Prins +10 more
TL;DR: Phylogenetic analysis showed that the majority of the HCV-positive, first-generation non-Western non-European migrants were infected with endemic strains which are rarely observed in Europe.
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Pneumocystis pneumonia in patients with rheumatic diseases receiving prolonged, non-high-dose steroids—clinical implication of primary prophylaxis using trimethoprim–sulfamethoxazole
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References
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Book
Regression Diagnostics: Identifying Influential Data and Sources of Collinearity
TL;DR: In this article, the authors present a method for detecting and assessing Collinearity of observations and outliers in the context of extensions to the Wikipedia corpus, based on the concept of Influential Observations.
Journal ArticleDOI
Regression Diagnostics: Identifying Influential Data and Sources of Collinearity
TL;DR: This chapter discusses Detecting Influential Observations and Outliers, a method for assessing Collinearity, and its applications in medicine and science.
Journal Article
Statistical methods in cancer research. Volume I - The analysis of case-control studies.
N. E. Breslow,N. E. Day +1 more
Journal ArticleDOI
Bias reduction of maximum likelihood estimates
TL;DR: In this paper, the first-order term is removed from the asymptotic bias of maximum likelihood estimates by a suitable modification of the score function, and the effect is to penalize the likelihood by the Jeffreys invariant prior.
Book
Modelling Survival Data in Medical Research
TL;DR: This paper discusses the design of clinical trials, use of computer software in survival analysis, and some non-parametric procedures for modelling survival data.