Abstract:
:We survey models for analysing repeated observations on an ordered categorical response variable. The models presented are univariate models that permit correlation among repeated measurements. The models describe simultaneously the dependence of marginal response distributions on values of explanatory variables and on the occasion of response. We present models for three transformations of the response distribution: cumulative logits, adjacent-category logits, and the mean for scores assigned to response categories. We discuss three methods for fitting the models: maximum likelihood, weighted least squares, and semi-parametric. Weighted least squares is easily implemented with SAS, as illustrated with a study designed to compare a drug with a placebo for the treatment of insomnia.
journal_name
Stat Medjournal_title
Statistics in medicineauthors
Agresti Adoi
10.1002/sim.4780081005subject
Has Abstractpub_date
1989-10-01 00:00:00pages
1209-24issue
10eissn
0277-6715issn
1097-0258journal_volume
8pub_type
杂志文章abstract::We develop analysis methods for clinical trials with time-to-event outcomes which correct for treatment changes during follow-up, yet are based on comparisons of randomized groups and not of selected groups. A causal model relating observed event times to event times that would have been observed under other treatment...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19991015)18:19<2617::aid-s
更新日期:1999-10-15 00:00:00
abstract::Case-control studies are usually defined to investigate risk factors for a single disease of interest. However, subsequent to data collection, investigators may wish to examine as an 'outcome' a variable that was an exposure in the original study. A naive analysis that disregards the sampling strategy that gave rise t...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2398
更新日期:2005-12-30 00:00:00
abstract::In many chronic diseases, therapy aims to prevent or reduce the frequency of episodes of a disease manifestation, for example cardiac ischaemic episodes or epileptic seizures. Entry criteria for clinical trials typically include a minimum number of episodes within a baseline period, and regression to the mean should b...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780130806
更新日期:1994-04-30 00:00:00
abstract::When investigating health disparities, it can be of interest to explore whether adjustment for socioeconomic factors at the neighborhood level can account for, or even reverse, an unadjusted difference. Recently, we proposed new methods to adjust the effect of an individual-level covariate for confounding by unmeasure...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5624
更新日期:2013-04-15 00:00:00
abstract::Orthogonal polynomial scores (OPS) is a simple, biologically meaningful approach to characterize longitudinal data in phase I and II clinical pharmacology trials. It describes average, linear, quadratic and higher order polynomial characteristics of each subject's response over time with use of composite scores comput...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780120703
更新日期:1993-04-15 00:00:00
abstract::The construction, validation and updating of a prognostic model for kidney graft survival is reported using data from the Eurotransplant database. First, a model is constructed for data from transplantations in the period 1984 to 1987. The model is later updated for the 1988 1990 data. The first data set was randomly ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780141806
更新日期:1995-09-30 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::The Rvachev-Baroyan-Longini model is a space-time predictive model of the spread of influenza epidemics. It has been applied to 128 cities of the USSR, and more recently, to forecasting the spread of the pandemic of 1968-1969 throughout 52 large cities. It is a deterministic, mass-action, space and time continuous mod...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780071107
更新日期:1988-11-01 00:00:00
abstract::In many medical applications, combining information from multiple biomarkers could yield a better diagnosis than any single one on its own. When there is a lack of a gold standard, an algorithm of classifying subjects into the case and non-case status is necessary for combining multiple markers. The aim of this paper ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6780
更新日期:2016-04-15 00:00:00
abstract::In a recent Statistics in Medicine paper, Warn, Thompson and Spiegelhalter (WTS) made a comparison between the Bayesian approach to the meta-analysis of binary outcomes and a popular Classical approach that uses summary (two-stage) techniques. They included approximate summary (two-stage) Bayesian techniques in their ...
journal_title:Statistics in medicine
pub_type: 评论,信件
doi:10.1002/sim.2115
更新日期:2005-09-15 00:00:00
abstract::In longitudinal studies, missing observations occur commonly. It has been well known that biased results could be produced if missingness is not properly handled in the analysis. Authors have developed many methods with the focus on either incomplete response or missing covariate observations, but rarely on both. The ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5536
更新日期:2013-02-28 00:00:00
abstract::In many studies, interest lies in determining whether members of the study population will undergo a particular event of interest. Such scenarios are often termed 'mover-stayer' scenarios, and interest lies in modelling two sub-populations of 'movers' (those who have a propensity to undergo the event of interest) and ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5529
更新日期:2013-02-20 00:00:00
abstract::A new method is proposed for the surveillance of Down's syndrome among newborn. Despite the strong dependence of overall risk of Down's syndrome on maternal age, it has been suggested that an environmentally induced increase in risk may be additive over all maternal ages. The surveillance method introduced here is spe...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780120104
更新日期:1993-01-15 00:00:00
abstract::This paper considers the regression analysis of CD4 cell counts, a commonly used indicator and prognostic factor of AIDS progression. For this purpose, a number of methods have been proposed and most of them are based on random effects models. We present an alternative that is based on a mean function regression model...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.945
更新日期:2001-11-15 00:00:00
abstract::Typical analyses of lifetime data treat the time to death or failure as the response variable and use a variety of modelling strategies such as proportional hazards or fully parametric, to investigate the relationship between the response and covariates. In certain circumstances it may be more natural to view the dist...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.822
更新日期:2001-07-15 00:00:00
abstract::We consider several sources of heterogeneity in a clinical trial with patients' survival time as the main response criterion: differences in prognosis which can be attributed to a latent or ignored prognostic factor; differences in treatment efficacy in subgroups of patients, and differences in treatment combinations ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780060708
更新日期:1987-10-01 00:00:00
abstract::Studies involving longitudinal binary responses are widely applied in the health and biomedical sciences research and frequently analyzed by generalized estimating equations (GEE) method. This article proposes an alternative goodness-of-fit test based on the nonparametric smoothing approach for assessing the adequacy ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3315
更新日期:2008-09-30 00:00:00
abstract::Composite endpoints are frequently used in clinical trials, but simple approaches, such as the time to first event, do not reflect any ordering among the endpoints. However, some endpoints, such as mortality, are worse than others. A variety of procedures have been proposed to reflect the severity of the individual en...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8431
更新日期:2020-02-28 00:00:00
abstract::Comparative calibration is the broad statistical methodology used to assess the calibration of a set of p instruments, each designed to measure the same characteristic, on a common group of individuals. Different from the usual calibration problem, the true underlying quantity measured is unobservable. Many authors ha...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19970830)16:16<1889::aid-s
更新日期:1997-08-30 00:00:00
abstract::In biomedical studies and clinical trials, repeated measures are often subject to some upper and/or lower limits of detection. Hence, the responses are either left or right censored. A complication arises when more than one series of responses is repeatedly collected on each subject at irregular intervals over a perio...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8017
更新日期:2019-03-15 00:00:00
abstract::A technique is presented which provides guidance on the spacing of follow-up waves in a multiwave study. Only information from the baseline wave is needed, as well as rough parameter estimates for the survival distribution. The computations use the expected Fisher information; a new method for its calculation is given...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780101209
更新日期:1991-12-01 00:00:00
abstract::The serial dilution assay (for example, an in vitro antimicrobic susceptibility test or a serum antibody titer assay) is an important technique in biomedical research. The structure of the experiment forces grouping of the threshold concentrations into intervals. Statistical methods to analyse threshold concentrations...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780070410
更新日期:1988-04-01 00:00:00
abstract::Case-control studies are prone to low power for testing gene-environment interactions (GXE) given the need for a sufficient number of individuals on each strata of disease, gene, and environment. We propose a new study design to increase power by strategically pooling biospecimens. Pooling biospecimens allows us to in...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5357
更新日期:2012-11-20 00:00:00
abstract::Pooling biospecimens prior to performing lab assays can help reduce lab costs, preserve specimens, and reduce information loss when subject to a limit of detection. Because many biomarkers measured in epidemiological studies are positive and right-skewed, proper analysis of pooled specimens requires special methods. I...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6496
更新日期:2015-07-30 00:00:00
abstract::Incomplete and unbalanced multivariate data often arise in longitudinal studies due to missing or unequally-timed repeated measurements and/or the presence of time-varying covariates. A general approach to analysing such data is through maximum likelihood analysis using a linear model for the expected responses, and s...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780070132
更新日期:1988-01-01 00:00:00
abstract::The microbiome plays an important role in human health by mediating the path from environmental exposures to health outcomes. The relative abundances of the high-dimensional microbiome data have an unit-sum restriction, rendering standard statistical methods in the Euclidean space invalid. To address this problem, we ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8808
更新日期:2021-02-20 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::The World Health Organization and collaborating institutions in four developing countries have conducted a multi-centre randomized controlled trial, in which clinics were allocated at random to two antenatal care (ANC) models. These were the standard 'Western' ANC model and a 'new' ANC model consisting of tests, clini...
journal_title:Statistics in medicine
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1002/1097-0258(20010215)20:3<401::aid-sim801>3.
更新日期:2001-02-15 00:00:00
abstract::We propose a joint model for a time-to-event outcome and a quantile of a continuous response repeatedly measured over time. The quantile and survival processes are associated via shared latent and manifest variables. Our joint model provides a flexible approach to handle informative dropout in quantile regression. A M...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6393
更新日期:2015-03-30 00:00:00
abstract::Individuals may vary in their responses to treatment, and identification of subgroups differentially affected by a treatment is an important issue in medical research. The risk of misleading subgroup analyses has become well known, and some exploratory analyses can be helpful in clarifying how covariates potentially i...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7970
更新日期:2019-02-10 00:00:00