Journal ArticleDOI
A solution to the problem of separation in logistic regression
Georg Heinze,Michael Schemper +1 more
Reads0
Chats0
TLDR
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
Citations
More filters
Journal ArticleDOI
Cardiovascular MRI Predicts 5‐Year Adverse Clinical Outcome in Heart Transplant Recipients
Craig Butler,Daniel Kim,Kelvin Chow,Mustafa Toma,Richard B. Thompson,Michael Mengel,Mark J. Haykowsky,Glen J. Pearson,Ian Paterson +8 more
TL;DR: CMRI‐derived myocardial scar and RVEDVI are independently associated with CV outcomes in HTRs, and both are predictive of time to CV death or hospitalization.
Journal ArticleDOI
MicroRNA expression profiling and Notch1 and Notch2 expression in minimal deviation adenocarcinoma of uterine cervix.
Heejeong Lee,Kyu Rae Kim,Nam Hoon Cho,Sung Ran Hong,Hoiseon Jeong,Sun Young Kwon,Kwang Hwa Park,Hee Jung An,Tae Heon Kim,Insun Kim,Hye Kyoung Yoon,Kwang Sun Suh,Ki Ouk Min,Hyun Joo Choi,Jiyoung Park,Chong Woo Yoo,Youn Soo Lee,Hee Jin Lee,Weon Sun Lee,Chul Soo Park,Yonghee Lee +20 more
TL;DR: MDA showed distinctive expression profiles of miRNAs, Notch1, and Notch2 from normal proliferative endocervical tissues and the miR-34b-5p/Notch1 pathway as well as Notch 2 might be important oncogenic contributors to MDA.
Journal ArticleDOI
The intratumoral CXCR3 chemokine system is predictive of chemotherapy response in human bladder cancer.
Tino Vollmer,Stephan Schlickeiser,Leila Amini,Sarah Schulenberg,Desiree J. Wendering,Viqar Showkat Banday,Anke Jurisch,Rebecca Noster,Désirée Kunkel,Nicola Brindle,Ioannis Savidis,Levent Akyüz,Jochen Hecht,Ulrik Stervbo,Toralf Roch,Toralf Roch,Nina Babel,Nina Babel,Petra Reinke,Ola Winqvist,Amir Sherif,Hans-Dieter Volk,Michael Schmueck-Henneresse +22 more
TL;DR: In this article, the role of CD8+ T cell infiltration in the success of chemotherapy was examined in patients with muscle invasive bladder cancer (MIBC) who were categorized on the basis of the response to neoadjuvant chemotherapy (NAC).
Journal ArticleDOI
Groove pancreatitis, a masquerading yet distinct clinicopathological entity: Analysis of risk factors and differentiation
Veeral M. Oza,Jacob Skeans,Peter Muscarella,Jon P. Walker,Brett C. Sklaw,Kevin M. Cronley,Samer El-Dika,Benjamin Swanson,Alice Hinton,Darwin L. Conwell,Somashekar G. Krishna +10 more
TL;DR: Groove pancreatitis in the HOP is associated with a history of heavy EtOH and weight loss, and in the absence of these symptoms, it is essential to rule out a malignant lesion.
Journal ArticleDOI
Effectiveness of Monovalent 2009 Pandemic Influenza A Virus Subtype H1N1 and 2010–2011 Trivalent Inactivated Influenza Vaccines in Wisconsin During the 2010–2011 Influenza Season
Allen C. Bateman,Burney A. Kieke,Stephanie A. Irving,Jennifer K. Meece,David K. Shay,Edward A. Belongia +5 more
TL;DR: Monovalent vaccine provided no sustained protection against A(H1N1)pdm09 infection during the 2010-2011 season, and waning effectiveness supports the need for annual revaccination.
References
More filters
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.