Abstract:
:The relative importance of prognostic factors in regression can be measured either by standardized regression coefficients or by percentages of explained variation in a dependent variable. One advantage of using explained variation is the direct comparability of qualitative prognostic factors with others, or of groups of prognostic factors. The description of relative importance can be accomplished within marginal or partial effects analyses. It is demonstrated that it is possible not only to provide a descriptive ranking of prognostic factors according to their statistically determined importance, but also to make inferences concerning their relative importance, employing bootstrap techniques and procedures for multiple comparisons. The methods presented, which are new in the context of Cox regression, are exemplified by analyses of studies of lung cancer and breast cancer.
journal_name
Stat Medjournal_title
Statistics in medicineauthors
Schemper Mdoi
10.1002/sim.4780122413subject
Has Abstractpub_date
1993-12-30 00:00:00pages
2377-82issue
24eissn
0277-6715issn
1097-0258journal_volume
12pub_type
杂志文章abstract::Rao proposed and compared several approaches for predicting future observations in a growth curve model. The assessment of associated prediction efficiency for different prediction methods were evaluated by Cross-Validation Assessment Error (CVAE). He used three data sets, each with a limited number of subjects (13-27...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780132103
更新日期:1994-11-15 00:00:00
abstract::The back-calculation method has been used to estimate the number of HIV infections from AIDS incidence data in a particular population. We present an extension of back calculation that provides estimates of the numbers of HIV infectives in different stages of infection. We model the staging process with a time-depende...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780110612
更新日期:1992-04-01 00:00:00
abstract::Assessing the QT prolongation potential of a drug is typically done based on pivotal safety studies called thorough QT studies. Model-based estimation of the drug-induced QT prolongation at the estimated mean maximum drug concentration could increase efficiency over the currently used intersection-union test. However,...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7395
更新日期:2017-10-30 00:00:00
abstract::A popular method for analysing repeated-measures data is generalized estimating equations (GEE). When response data are missing at random (MAR), two modifications of GEE use inverse-probability weighting and imputation. The weighted GEE (WGEE) method involves weighting observations by their inverse probability of bein...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3520
更新日期:2009-03-15 00:00:00
abstract:BACKGROUND:The need to deliver interventions targeting multiple diseases in a cost-effective manner calls for integrated disease control efforts. Consequently, maps are required that show where the risk of co-infection is particularly high. Co-infection risk is preferably estimated via Bayesian geostatistical multinomi...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4243
更新日期:2011-06-30 00:00:00
abstract::Repeated cross-sectional samples are common in national surveys of health like the National Health Interview Survey (NHIS). Because population health outcomes generally evolve slowly, pooling data across years can improve the precision of current-year annual estimates of disease prevalence and other health outcomes. P...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3897
更新日期:2011-02-28 00:00:00
abstract::In this paper we describe Bonferroni-based multiple testing procedures (MTPs) as strategies to split and recycle test mass. Here, 'test mass' refers to (parts of) the nominal level alpha at which the family-wise error rate is controlled. Briefly, test mass is split between different null hypotheses, and whenever a nul...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3513
更新日期:2009-02-28 00:00:00
abstract::Shared random effects models have been increasingly common in the joint analyses of repeated measures (e.g. CD4 counts, hemoglobin levels) and a correlated failure time such as death. In this paper we study several shared random effects models in the multi-level repeated measures data setting with dependent failure ti...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3392
更新日期:2008-11-29 00:00:00
abstract::To benefit Alzheimer's disease research, a central data co-ordinating centre (CDCC) is planned that will systematically collect data from 27 Alzheimer's disease centres (ADCs) located nationwide. This CDCC will combine, analyse and disseminate epidemiologic, demographic, clinical and neuropathological data to research...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(20000615/30)19:11/12<1453:
更新日期:2000-06-15 00:00:00
abstract::A new, intuitive method has recently been proposed to explore treatment-covariate interactions in survival data arising from two treatment arms of a clinical trial. The method is based on constructing overlapping subpopulations of patients with respect to one (or more) covariates of interest and in observing the patte...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3524
更新日期:2009-04-15 00:00:00
abstract::The primary goal of a phase I trial is to find the maximally tolerated dose (MTD) of a treatment. The MTD is usually defined in terms of a tolerable probability, q(*), of toxicity. Our objective is to find the highest dose with toxicity risk that does not exceed q(*), a criterion that is often desired in designing pha...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.970
更新日期:2002-01-15 00:00:00
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journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6973
更新日期:2016-09-10 00:00:00
abstract::Lung function tests are used both clinically, in assessing disease, and epidemiologically, in identifying those factors which influence the growth and aging process of the lungs. The user must beware of several common pitfalls in the use of these tests, however. First, the commonly used tests of lung function can only...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780070106
更新日期:1988-01-01 00:00:00
abstract::Biostatistical concepts and methods apply to various problems arising in actual U.S. legal cases. These involve: measures of association, assessing the potential effect of omitted variables and the Peters-Belson approach to regression. In particular, we present the inapplicability of Fisher's exact test in the case wh...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780141505
更新日期:1995-08-15 00:00:00
abstract::The primary purpose of a disease surveillance system is to provide data for the detection of changes in the incidence of the disease. Methods for the analysis of data from surveillance systems are reviewed. A new procedure is proposed for use when the system includes geographically dispersed reporting units, such as h...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780080306
更新日期:1989-03-01 00:00:00
abstract::The change in c-statistic is frequently used to summarize the change in predictive accuracy when a novel risk factor is added to an existing logistic regression model. We explored the relationship between the absolute change in the c-statistic, Brier score, generalized R(2) , and the discrimination slope when a risk f...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5598
更新日期:2013-02-20 00:00:00
abstract::Elevated plasma levels of apolipoproteins A1 (apoA1) and B (apoB) are important protective factors and risk factors, respectively, for atherosclerosis and coronary heart disease. It is well known that both apoA1 and apoB reveal strong familial aggregation. Our goal was to investigate whether exogenous variables influe...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/1097-0258(20001230)19:24<3345::aid-sim829>
更新日期:2000-12-30 00:00:00
abstract::A considerable number of the clinical reports which are presented to the Dutch Board for the Evaluation of Drugs, have deficiencies and/or shortcomings. A number of these, including loose description of the target population and sampling method, methodological flaws, incorrect treatment of withdrawals, confounding of ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780020209
更新日期:1983-04-01 00:00:00
abstract::A mediator acts as a third variable in the causal pathway between a risk factor and an outcome. In this paper, we consider the estimation of the mediation effect when the mediator is a binary variable. We give a precise definition of the mediation effect and examine asymptotic properties of five different estimators o...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2730
更新日期:2007-08-15 00:00:00
abstract::This paper considers the analysis of longitudinal data complicated by the fact that during follow-up patients can be in different disease states, such as remission, relapse or death. If both the response of interest (for example, quality of life (QOL)) and the amount of missing data depend on this disease state, ignor...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3755
更新日期:2009-12-30 00:00:00
abstract::We applied a two-stage random effects model to pulmonary function data from 31 sarcoidosis patients to illustrate its usefulness in analysing unbalanced longitudinal data. For the first stage, repeated measurements of percentage of predicted forced vital capacity (FVC%) from an individual were modelled as a function o...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780080206
更新日期:1989-02-01 00:00:00
abstract::Small but important therapeutic effects of new treatments can be most efficiently detected through the study of large randomized prospective series of patients. Such large scale clinical trials are nowadays commonplace. The alternative is years of polemic and debate surrounding several trials each too small to detect ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780010105
更新日期:1982-01-01 00:00:00
abstract::In this paper, an approach to estimating the cumulative mean function for history process with time dependent covariates and right censored time-to-event variable is developed using the combined technique of joint modeling and inverse probability weighting method. The consistency of proposed estimator is derived. Theo...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6998
更新日期:2016-11-10 00:00:00
abstract::Maps of estimated disease rates over multiple time periods are useful tools for gaining etiologic insights regarding potential exposures associated with specific locations and times. In this paper, we describe an extension of the Gangnon-Clayton model for spatial clustering to spatio-temporal data. As in the purely sp...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3984
更新日期:2010-09-30 00:00:00
abstract::Motivated by a previously published study of HIV treatment, we simulated data subject to time-varying confounding affected by prior treatment to examine some finite-sample properties of marginal structural Cox proportional hazards models. We compared (a) unadjusted, (b) regression-adjusted, (c) unstabilized, and (d) s...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5317
更新日期:2012-08-30 00:00:00
abstract::In behavioral, biomedical, and social-psychological sciences, it is common to encounter latent variables and heterogeneous data. Mixture structural equation models (SEMs) are very useful methods to analyze these kinds of data. Moreover, the presence of missing data, including both missing responses and missing covaria...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3915
更新日期:2010-08-15 00:00:00
abstract::Day and Walter derived methods of joint maximum likelihood estimation for the sojourn time distribution and the false negative rate for a screening programme. Their methods are not directly applicable to a programme which uses alternate screening by two modalities whose sojourn times and false negative rates will diff...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780080611
更新日期:1989-06-01 00:00:00
abstract::Comparative effectiveness research represents the kind of research that arguably more directly affects clinical practice and policy. It includes observational studies, clinical trials, and systematic syntheses of existing literature. In this commentary, I argue for the ongoing and critical role of randomization in com...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5400
更新日期:2012-11-10 00:00:00
abstract::Timeliness of a public health surveillance system is one of its most important characteristics. The process of predicting the present situation using available incomplete information from surveillance systems has received the term nowcasting and has high public health interest. Generally in Europe, general practitione...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5670
更新日期:2013-07-10 00:00:00
abstract::Various aspects of portfolio management and project prioritization within the pharmaceutical industry are examined. It is shown that the cost and probability architecture of a project is a crucial aspect of its value. An appropriate simple tool for ranking projects is the Pearson index. Various difficulties are consid...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(SICI)1097-0258(19961230)15:24<2689::AID-S
更新日期:1996-12-30 00:00:00