Abstract:
:Proportional odds regression models for multinomial probabilities based on ordered categories have been generalized in two somewhat different directions. Models having scale as well as location parameters for adjustment of boundaries (on an unobservable, underlying continuum) between categories have been employed in the context of ROC analysis. Partial proportional odds models, having different regression adjustments for different multinomial categories, have also been proposed. This paper considers a synthesis and further generalization of these two families. With use of a number of examples, I discuss and illustrate properties of this extended family of models. Emphasis is on the computation of maximum likelihood estimates of parameters, asymptotic standard deviations, and goodness-of-fit statistics with use of non-linear regression programs in standard statistical software such as SAS.
journal_name
Stat Medjournal_title
Statistics in medicineauthors
Cox Cdoi
10.1002/sim.4780141105subject
Has Abstractpub_date
1995-06-15 00:00:00pages
1191-203issue
11eissn
0277-6715issn
1097-0258journal_volume
14pub_type
杂志文章abstract::A number of variance formulae for the attributable fraction have been presented, but none is consistent in sparse data, such as found in individually matched case-control studies. This paper employs Mantel-Haenszel estimation to derive variance estimators for attributable fractions that are dually consistent, that is,...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780060607
更新日期:1987-09-01 00:00:00
abstract::This paper models monthly AIDS diagnosis counts in terms of smooth secular trend, calendar month effects, and the number of workdays per month. A parameterization of month effects allows separation of true seasonal effects from a linear trend over the calendar year and an arbitrary June effect. There is strong evidenc...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780131905
更新日期:1994-10-15 00:00:00
abstract::The goal of phase I cancer trials is to determine the highest dose of a treatment regimen with an acceptable toxicity rate. Traditional designs for phase I trials, such as the Continual Reassessment Method (CRM) and the 3 + 3 design, require each patient or a cohort of patients to be fully evaluated for the dose-limit...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4255
更新日期:2011-07-30 00:00:00
abstract::Statistical modeling methods have had increasing use in drug disposition studies, both to estimate pharmacokinetic parameters and to develop regression models that relate these parameter estimates to patient characteristics. These methods are particularly flexible as they allow non-linearity and sparse within-patient ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19970615)16:11<1241::aid-s
更新日期:1997-06-15 00:00:00
abstract::The purpose of this paper is to show that the sensitivity and specificity estimates obtained by 'discrepant analysis' are biased. Discrepant analysis is a widely used technique that attempts to provide estimates of sensitivity and specificity in the presence of an imperfect gold standard. Many researchers have applied...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19970630)16:12<1391::aid-s
更新日期:1997-06-30 00:00:00
abstract::Many observational studies adopt what we call retrospective convenience sampling (RCS). With the sample size in each arm prespecified, RCS randomly selects subjects from the treatment-inclined subpopulation into the treatment arm and those from the control-inclined into the control arm. Samples in each arm are represe...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7808
更新日期:2018-05-20 00:00:00
abstract::We describe the usual statistical concepts and consequent appropriate simulations of a prospective study for the simple case of a single risk variable and an assumed logistic model. We examine the simulations of Lilienfeld and Pyne, and show that they are seriously flawed. Contrary to those authors' claims, the estima...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780040212
更新日期:1985-04-01 00:00:00
abstract::We consider using observational data to estimate the effect of a treatment on disease recurrence, when the decision to initiate treatment is based on longitudinal factors associated with the risk of recurrence. The effect of salvage androgen deprivation therapy (SADT) on the risk of recurrence of prostate cancer is in...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4017
更新日期:2010-11-10 00:00:00
abstract::The FDA Guidance, while highly appropriate for industry sponsored trials, need not be imposed on publicly (e.g. NIH) financed clinical trials. While the potential for conflicts of interest exist in the latter, they are in general manageable and pose an acceptable low risk of threatening the integrity of a study. Howev...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1787
更新日期:2004-05-30 00:00:00
abstract::In genetic association studies, it is typically thought that genetic variants and environmental variables jointly will explain more of the inheritance of a phenotype than either of these two components separately. Traditional methods to identify gene-environment interactions typically consider only one measured enviro...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5444
更新日期:2013-01-30 00:00:00
abstract::Prevalence data provided by cancer registries are generally biased, since the patients that were diagnosed before the starting of the registry's activity cannot be included in the statistics. The relevance of this incompleteness bias is estimated in this paper. Incidence and relative survival are modelled as parametri...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19970228)16:4<425::aid-sim
更新日期:1997-02-28 00:00:00
abstract::The two-period cross-over design with two sequences of drug administration is a standard experimental design when bioequivalence of one test formulation is to be assessed in comparison with a reference formulation. Previously, an approach based on Fieller's confidence interval has been presented for the assessment of ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19971015)16:19<2229::aid-s
更新日期:1997-10-15 00:00:00
abstract::In cancer clinical trials, patients often experience a recurrence of disease prior to the outcome of interest, overall survival. Additionally, for many cancers, there is a cured fraction of the population who will never experience a recurrence. There is often interest in how different covariates affect the probability...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6056
更新日期:2014-05-10 00:00:00
abstract::We propose a probability distribution for an equivalence class of classification trees (that is, those that ignore the value of the cutpoints but retain tree structure). This distribution is parameterized by a central tree structure representing the true model, and a precision or concentration coefficient representing...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19990330)18:6<727::aid-sim
更新日期:1999-03-30 00:00:00
abstract::Researchers in clinical science and bioinformatics frequently aim to learn which of a set of candidate biomarkers is important in determining a given outcome, and to rank the contributions of the candidates accordingly. This article introduces a new approach to research questions of this type, based on targeted maximu...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3414
更新日期:2009-01-15 00:00:00
abstract::Disease incidence predictions are useful for a number of administrative and scientific purposes. The simplest ones are made using trend extrapolation, on either an arithmetic or a logarithmic scale. This paper shows how approximate confidence prediction intervals can be calculated for such predictions, both for the to...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780131503
更新日期:1994-08-15 00:00:00
abstract::Instrumental variable is an essential tool for addressing unmeasured confounding in observational studies. Two-stage predictor substitution (2SPS) estimator and two-stage residual inclusion (2SRI) are two commonly used approaches in applying instrumental variables. Recently, 2SPS was studied under the additive hazards...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8071
更新日期:2019-05-10 00:00:00
abstract::Ordinal data appear in a wide variety of scientific fields. These data are often analyzed using ordinal logistic regression models that assume proportional odds. When this assumption is not met, it may be possible to capture the lack of proportionality using a constrained structural relationship between the odds and t...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5689
更新日期:2013-06-15 00:00:00
abstract::To study the spread of sexually transmitted diseases (STDs) using social/sexual mixing models, one must have quantitative information about sexual mixing. An unavoidable complication in gathering such information by survey is that members of the surveyed population will almost certainly have sexual contacts outside th...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780111202
更新日期:1992-09-15 00:00:00
abstract::The stability-controlled quasi-experiment (SCQE) is an approach to study the effects of nonrandomized, newly adopted treatments. While covariate adjustment techniques rely on a "no unobserved confounding" assumption, SCQE imposes an assumption on the change in the average nontreatment outcome between successive cohort...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8717
更新日期:2020-12-10 00:00:00
abstract::Down's syndrome screening is currently carried out using a combination of biochemical markers measured in maternal serum samples; these include MSAFP, Total hCG, uE3 and Free beta-hCG. Recently a number of papers have compared the effectiveness of different combinations of these markers. Some recommend MSAFP, Total hC...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19970715)16:13<1481::aid-s
更新日期:1997-07-15 00:00:00
abstract::Regression to the mean arises often in statistical applications where the units chosen for study relate to some observed characteristic in the extreme of its distribution. Gardner and Heady attribute the effect of regression to the mean to measurement errors. They assume the model Yi = U + ei, where U is a fixed withi...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780100812
更新日期:1991-08-01 00:00:00
abstract::Huntington's disease (HD) is a neurodegenerative disorder with a dominant genetic mode of inheritance caused by an expansion of CAG repeats on chromosome 4. Typically, a longer sequence of CAG repeat length is associated with increased risk of experiencing earlier onset of HD. Previous studies of the association betwe...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5971
更新日期:2014-04-15 00:00:00
abstract::While there has been extensive research developing gene-environment interaction (GEI) methods in case-control studies, little attention has been given to sparse and efficient modeling of GEI in longitudinal studies. In a two-way table for GEI with rows and columns as categorical variables, a conventional saturated int...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6281
更新日期:2014-12-20 00:00:00
abstract::This paper is a compendium of exact and asymptotic formulae and tables for estimating the sample size in a clinical trial with two treatment groups and a dichotomous outcome. The paper provides separate formulae for equal and unequal treatment group sizes, formulae for the calculation of power given the sample size, a...
journal_title:Statistics in medicine
pub_type: 杂志文章,评审
doi:10.1002/(SICI)1097-0258(19960115)15:1<1::AID-SIM13
更新日期:1996-01-15 00:00:00
abstract::In studies with survival or time-to-event outcomes, a competing risk is an event whose occurrence precludes the occurrence of the primary event of interest. Specialized statistical methods must be used to analyze survival data in the presence of competing risks. We conducted a review of randomized controlled trials wi...
journal_title:Statistics in medicine
pub_type: 杂志文章,评审
doi:10.1002/sim.7215
更新日期:2017-04-15 00:00:00
abstract::We analyze data obtained from a study designed to evaluate training effects on the performance of certain motor activities of Parkinson's disease patients. Maximum likelihood methods were used to fit beta-binomial/Poisson regression models tailored to evaluate the effects of training on the numbers of attempted and su...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3303
更新日期:2008-07-30 00:00:00
abstract::It is often assumed that randomisation will prevent bias in estimation of treatment effects from clinical trials, but this is not true of the semiparametric Proportional Hazards model for survival data when there is underlying risk heterogeneity. Here, a new formula is proposed for estimation of this bias, improving o...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7343
更新日期:2017-09-20 00:00:00
abstract::Multi-state models are useful for modelling disease progression where the state space of the process is used to represent the discrete disease status of subjects. Often, the disease process is only observed at clinical visits, and the schedule of these visits can depend on the disease status of patients. In such situa...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6582
更新日期:2015-12-20 00:00:00
abstract::We describe how trends in the vaccination coverage at 19 months of age vary by race/ethnicity; explore the extent to which data required to evaluate a child's up-to-date vaccination status is missing as a result of the scattering of vaccination records among many vaccination providers; evaluate how the prevalence of t...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3223
更新日期:2008-09-10 00:00:00