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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Epidemiology of Diabetes Mellitus among 193,435 Cats Attending Primary-Care Veterinary Practices in England
Dan G. O’Neill,Ruth Gostelow,C Orme,David B. Church,Stijn J. M. Niessen,Kristien Verheyen,Dave C. Brodbelt +6 more
TL;DR: An increased risk of DM in certain cat breeds supports a genetic predisposition and can guide future research and preventative healthcare.
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A comparison of statistical learning methods for deriving determining factors of accident occurrence from an imbalanced high resolution dataset
TL;DR: This analysis employs and compares a series of statistical learning techniques with respect to their predictive performance and discusses the importance of determining factors of accident occurrence from the ensemble of models, substantiate that a trade-off between accuracy and sensitivity is inherent to imbalanced classification problems.
Journal ArticleDOI
Bone presence between the central peg's radial fins of a partially cemented pegged all poly glenoid component suggest few radiolucencies
TL;DR: TSA utilizing autologous bone in inter-fin compartments of the central peg and minimal peripheral peg cement maintained bone presence a minimum 2 years post-op, with better bone presence between the radial fins associated with less overall radiolucencies.
Journal ArticleDOI
Comparing Outcomes of Robotic and Open Inguinal Lymph Node Dissection in Patients with Carcinoma of the Penis
Amitabh Singh,Jiten Jaipuria,Amit Goel,Swati Shah,Raghubir Bhardwaj,Saroj Baidya,Jalaj Jain,Chirag Jain,Sudhir Rawal +8 more
TL;DR: Robot‐assisted video endoscopic inguinal lymphadenectomy is a feasible technique which allows for a similar nodal yield while being associated with lower morbidity than open ingUinal lymph node dissection in patients without bulky groin adenopathy.
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Predictors of secondary school completion among refugee youth 8 to 9 years after resettlement in Melbourne, Australia
TL;DR: This paper found that refugee youth are particularly at risk of not completing secondary school education, which can have an impact on their wellbeing and long-term socio-economic standing in their settlement country.
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.