Variance estimators for attributable fraction estimates consistent in both large strata and sparse data.

abstract：:The setting of a quarantine time for an emerging infectious disease will depend on current knowledge concerning incubation times. Methods for the analysis of information on incubation times are investigated with a particular focus on inference regarding a possible maximum incubation time, after which an exposed indivi...

journal_title：Statistics in medicine

authors： Farewell VT,Herzberg AM,James KW,Ho LM,Leung GM

更新日期：2005-11-30 00:00:00

abstract：:In many medical and health studies, high-dimensional data are often encountered. Principal component analysis (PCA) is a commonly used technique to reduce such data to a few components that includes most of the information provided by the original data. However, PCA is known to be very sensitive to some abnormal obser...

journal_title：Statistics in medicine

authors： Fung WK,Gu H,Xiang L,Yau KK

更新日期：2007-06-15 00:00:00

abstract：:Many extensions of survival models based on the Cox proportional hazards approach have been proposed to handle clustered or multiple event data. Of particular note are five Cox-based models for recurrent event data: Andersen and Gill (AG); Wei, Lin and Weissfeld (WLW); Prentice, Williams and Peterson, total time (PWP-...

journal_title：Statistics in medicine

authors： Kelly PJ,Lim LL

更新日期：2000-01-15 00:00:00

abstract：:Cancer immunotherapy trials have two special features: a delayed treatment effect and a cure rate. Both features violate the proportional hazard model assumption and ignoring either one of the two features in an immunotherapy trial design will result in substantial loss of statistical power. To properly design immunot...

journal_title：Statistics in medicine

authors： Wei J,Wu J

更新日期：2020-03-15 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

authors： Polley MY

更新日期：2011-07-30 00:00:00

abstract：:In vaccine safety studies, subjects are considered at increased risk for adverse events for a period of time after vaccination known as risk window. To our knowledge, risk windows for vaccine safety studies have tended to be pre-defined and not to use information from the current study. Inaccurate specification of the...

journal_title：Statistics in medicine

authors： Xu S,Zhang L,Nelson JC,Zeng C,Mullooly J,McClure D,Glanz J

更新日期：2011-03-30 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

authors： Gastwirth JL,Greenhouse SW

更新日期：1995-08-15 00:00:00

abstract：:We studied the problem of testing a hypothesized distribution in survival regression models when the data is right censored and survival times are influenced by covariates. A modified chi-squared type test, known as Nikulin-Rao-Robson statistic, is applied for the comparison of accelerated failure time models. This st...

journal_title：Statistics in medicine

authors： Tahir MR,Tran QX,Nikulin MS

更新日期：2017-05-30 00:00:00

abstract：:The EQ-5D, a widely used multiattribute utility instrument, is commonly used in health economic evaluations where the goal is to decide on which treatments to reimburse. Like other instruments, value sets of the EQ-5D are constructed using valuation studies typically valuing a subset of the health states and using pre...

journal_title：Statistics in medicine

authors： Shams S,Pullenayegum E

更新日期：2020-10-15 00:00:00

abstract：:Although the frequentist paradigm has been the predominant approach to clinical trial design since the 1940s, it has several notable limitations. Advancements in computational algorithms and computer hardware have greatly enhanced the alternative Bayesian paradigm. Compared with its frequentist counterpart, the Bayesi...

journal_title：Statistics in medicine

authors： Lee JJ,Chu CT

更新日期：2012-11-10 00:00:00

abstract：:Longitudinal designs are important in medical research and in many other disciplines. Complete longitudinal studies, in which each subject is evaluated at each measurement occasion, are often very expensive and motivate a search for more efficient designs. Recently developed statistical methods foster the use of inten...

journal_title：Statistics in medicine

authors： Helms RW

更新日期：1992-10-01 00:00:00

abstract：:In comparing two treatments under a typical sequential clinical trial setting, a 50-50 randomization design generates reliable data for making efficient inferences about the treatment difference for the benefit of patients in the general population. However, if the treatment difference is large and the endpoint of the...

journal_title：Statistics in medicine

authors： Yao Q,Wei LJ

更新日期：1996-11-15 00:00:00

abstract：:The article is motivated by a nephrology study in Taiwan, which enrolled hemodialysis patients who suffered from vascular access thrombosis. After treatment, some patients were cured of thrombosis, while some may experience recurrence of either type (acute or nonacute) of vascular access thrombosis. Our major interest...

journal_title：Statistics in medicine

authors： Chen CM,Shen PS,Lin CC,Wu CC

更新日期：2020-11-30 00:00:00

abstract：:Although the literature on contraceptive failure is vast and is expanding rapidly, our understanding of the relative efficacy of methods is quite limited because of defects in the research design and in the analytical tools used by investigators. Errors in the literature range from simple arithmetical mistakes to outr...

journal_title：Statistics in medicine

authors： Trussell J

更新日期：1991-02-01 00:00:00

abstract：:The coefficient of individual equivalence is a permutation-based measure of agreement between two observers making replicated readings on each subject. It compares the observed disagreement between the observers to the expected disagreement under individual equivalence. Individual equivalence of observers requires tha...

journal_title：Statistics in medicine

authors： Pan Y,Haber M,Gao J,Barnhart HX

更新日期：2012-09-10 00:00:00

abstract：:Hospital length of stay (LOS) is an important measure of healthcare utilization and is generally positively skewed and heterogeneous. We fit a Coxian phase-type distribution to LOS and identify the hidden states of the underlying latent homogeneous Markov model. We demonstrate that selecting an appropriate number of p...

journal_title：Statistics in medicine

authors： Tang X,Luo Z,Gardiner JC

更新日期：2012-06-30 00:00:00

abstract：:In recent years randomized trials designed to establish non-inferiority of a new treatment as compared to a standard one have been more widely used. Two-sample statistics have been proposed for this equivalence testing problem. However, they are not suited to situations where a long-term survivor fraction is expected....

journal_title：Statistics in medicine

authors： Broët P,Tubert-Bitter P,De Rycke Y,Moreau T

更新日期：2003-03-30 00:00:00

abstract：:Missing data arise in crossover trials, as they do in any form of clinical trial. Several papers have addressed the problems that missing data create, although almost all of these assume that the probability that a planned observation is missing does not depend on the value that would have been observed; that is, the ...

journal_title：Statistics in medicine

authors： Ho WK,Matthews JN,Henderson R,Farewell D,Rodgers LR

更新日期：2012-07-20 00:00:00

abstract：:The statistical analysis of spatially correlated data has become an important scientific research topic lately. The analysis of the mortality or morbidity rates observed at different areas may help to decide if people living in certain locations are considered at higher risk than others. Once the statistical model for...

journal_title：Statistics in medicine

authors： Hsiao CK,Tzeng JY,Wang CH

更新日期：2000-07-30 00:00:00

abstract：:Prognostic models are used in medicine for investigating patient outcome in relation to patient and disease characteristics. Such models do not always work well in practice, so it is widely recommended that they need to be validated. The idea of validating a prognostic model is generally taken to mean establishing tha...

journal_title：Statistics in medicine

authors： Altman DG,Royston P

更新日期：2000-02-29 00:00:00

abstract：:Biomarkers, increasingly used in biomedical studies for the diagnosis and prognosis of acute and chronic diseases, provide insight into the effectiveness of treatments and potential pathways that can be used to guide future treatment targets. The measurement of these markers is often limited by the sensitivity of the ...

journal_title：Statistics in medicine

authors： Lee M,Kong L,Weissfeld L

更新日期：2012-07-30 00:00:00

abstract：:Pearson's chi-squared, the likelihood-ratio, and Fisher-Freeman-Halton's test statistics are often used to test the association of unordered r x c tables. Asymptotical, exact conditional, or exact conditional with mid-p adjustment methods are commonly used to compute the p-value. We have compared test power and signif...

journal_title：Statistics in medicine

authors： Lydersen S,Pradhan V,Senchaudhuri P,Laake P

更新日期：2007-10-15 00:00:00

abstract：:Many epidemiologic investigations are designed to study the effects of multiple exposures. Most of these studies are analysed either by fitting a risk-regression model with all exposures forced in the model, or by using a preliminary-testing algorithm, such as stepwise regression, to produce a smaller model. Research ...

journal_title：Statistics in medicine

authors： Greenland S

更新日期：1993-04-30 00:00:00

abstract：:It has been increasingly common to analyze simultaneously repeated measures and time to failure data. In this paper we propose a joint model when the repeated measures are semi-continuous, characterized by the presence of a large portion of zero values, as well as right skewness of non zero (positive) values. Examples...

journal_title：Statistics in medicine

authors： Liu L

更新日期：2009-03-15 00:00:00

abstract：:Estimating the causal effect of quitting smoking on time to death or first myocardial infarction requires that one control for the differences in risk factors between individuals who elect to quite at each time t versus those who elect to continue smoking at time t. In this paper we examine the limitations of standard...

journal_title：Statistics in medicine

authors： Mark SD,Robins JM

更新日期：1993-09-15 00:00:00

abstract：:Multi-type recurrent event data arise when two or more different kinds of events may occur repeatedly over a period of observation. The scientific objectives in such settings are often to describe features of the marginal processes and to study the association between the different types of events. Interval-censored m...

journal_title：Statistics in medicine

authors： Chen BE,Cook RJ,Lawless JF,Zhan M

更新日期：2005-03-15 00:00:00

abstract：:Delay in the outcome variable is challenging for outcome-adaptive randomization, as it creates a lag between the number of subjects accrued and the information known at the time of the analysis. Motivated by a real-life pediatric ulcerative colitis trial, we consider a case where a short-term predictor is available fo...

journal_title：Statistics in medicine

authors： Kim MO,Liu C,Hu F,Lee JJ

更新日期：2014-10-15 00:00:00

abstract：:Both traditional phase I designs and the increasingly popular continual reassessment method (CRM) designs select an estimate of maximum tolerable dose (MTD) from among a set of prespecified dose levels. Although CRM designs use an implied dose-response model to select the next dose level, in general it is neither assu...

journal_title：Statistics in medicine

authors： Storer BE

更新日期：2001-08-30 00:00:00

abstract：:In the analysis of composite endpoints in a clinical trial, time to first event analysis techniques such as the logrank test and Cox proportional hazard test do not take into account the multiplicity, importance, and the severity of events in the composite endpoint. Several generalized pairwise comparison analysis met...

journal_title：Statistics in medicine

authors： Verbeeck J,Spitzer E,de Vries T,van Es GA,Anderson WN,Van Mieghem NM,Leon MB,Molenberghs G,Tijssen J

更新日期：2019-12-30 00:00:00

abstract：:Two correction methods are considered for multiple logistic regression models with some covariates measured with error. Both methods are based on approximating the complicated regression model between the response and the observed covariates with simpler models. The first model is the logistic approximation proposed b...

journal_title：Statistics in medicine

authors： Kuha J

更新日期：1994-06-15 00:00:00