Mixtures of proportional hazards regression models.

abstract：:This paper describes a method for estimating the risk from a disease over a set of contiguous geographical regions, when data on a potentially important covariate, such as race, are not available. Conditions under which the extra margin can be recovered are suggested. An application to prostate cancer mortality among ...

journal_title：Statistics in medicine

authors： Byers S,Besag J

更新日期：2000-09-15 00:00:00

abstract：:When sample size is recalculated using unblinded interim data, use of the usual t-test at the end of a study may lead to an elevated type I error rate. This paper describes a numerical quadrature investigation to calculate the true probability of rejection as a function of the time of the recalculation, the magnitude ...

journal_title：Statistics in medicine

authors： Wittes J,Schabenberger O,Zucker D,Brittain E,Proschan M

更新日期：1999-12-30 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

authors： Lin KC,Chen YJ,Shyr Y

更新日期：2008-09-30 00:00:00

abstract：:There is an increasing interest in the use of propensity score methods to estimate causal effects in observational studies. However, recent systematic reviews have demonstrated that propensity score methods are inconsistently used and frequently poorly applied in the medical literature. In this study, we compared the ...

journal_title：Statistics in medicine

authors： Austin PC,Mamdani MM

更新日期：2006-06-30 00:00:00

abstract：:Inference for randomized clinical trials is generally based on the assumption that outcomes are independently and identically distributed under the null hypothesis. In some trials, particularly in infectious disease, outcomes may be correlated. This may be known in advance (e.g. allowing randomization of family member...

journal_title：Statistics in medicine

authors： Proschan M,Follmann D

更新日期：2008-03-15 00:00:00

abstract：:A mixture model incorporating long-term survivors has been adopted in the field of biostatistics where some individuals may never experience the failure event under study. The surviving fractions may be considered as cured. In most applications, the survival times are assumed to be independent. However, when the survi...

journal_title：Statistics in medicine

authors： Yau KK,Ng AS

更新日期：2001-06-15 00:00:00

abstract：:In multivariate network meta-analysis (NMA), the piecemeal nature of the evidence base means that there may be treatment-outcome combinations for which no data is available. Most existing multivariate evidence synthesis models are either unable to estimate the missing treatment-outcome combinations, or can only do so ...

journal_title：Statistics in medicine

authors： Waddingham E,Matthews PM,Ashby D

更新日期：2020-10-30 00:00:00

abstract：:A method has been developed for simultaneously comparing the usefulness of many treatments of established value for symptomatic medical conditions. Medical assessment of outcome is not employed. Instead patients are required to assess treatments prescribed during the course of ordinary general practice rather than und...

journal_title：Statistics in medicine

authors： Charlton JR,D'Souza MF,Tooley M,Silver R

更新日期：1985-01-01 00:00:00

abstract：:Relative potency is a measure that has been used for many years to summarize the comparison of dose-response curves in parallel line bioassays. When response curves for two preparations are not parallel the traditional definition of relative potency no longer applies. We review the concept of relative potency and show...

journal_title：Statistics in medicine

authors： Kaiser MS,Siev D

更新日期：1997-05-30 00:00:00

abstract：:The asymptotic Pearson's chi-squared test and Fisher's exact test have long been the most used for testing association in 2x2 tables. Unconditional tests preserve the significance level and generally are more powerful than Fisher's exact test for moderate to small samples, but previously were disadvantaged by being co...

journal_title：Statistics in medicine

authors： Lydersen S,Fagerland MW,Laake P

更新日期：2009-03-30 00:00:00

abstract：:In the medical literature, hundreds of prediction models are being developed to predict health outcomes in individuals. For continuous outcomes, typically a linear regression model is developed to predict an individual's outcome value conditional on values of multiple predictors (covariates). To improve model developm...

journal_title：Statistics in medicine

authors： Riley RD,Snell KIE,Ensor J,Burke DL,Harrell FE Jr,Moons KGM,Collins GS

更新日期：2019-03-30 00:00:00

abstract：:In this paper we study the problem of variable selection for the proportional odds model, which is a useful alternative to the proportional hazards model and might be appropriate when the proportional hazards assumption is not satisfied. We propose to fit the proportional odds model by maximizing the marginal likeliho...

journal_title：Statistics in medicine

authors： Lu W,Zhang HH

更新日期：2007-09-10 00:00:00

abstract：:Testing the equality of 2 proportions for a control group versus a treatment group is a well-researched statistical problem. In some settings, there may be strong historical data that allow one to reliably expect that the control proportion is one, or nearly so. While one-sample tests or comparisons to historical cont...

journal_title：Statistics in medicine

authors： Gabriel EE,Nason M,Fay MP,Follmann DA

更新日期：2018-03-30 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

authors： Burman CF,Sonesson C,Guilbaud O

更新日期：2009-02-28 00:00:00

abstract：:The incremental life expectancy, defined as the difference in mean survival times between two treatment groups, is a crucial quantity of interest in cost-effectiveness analyses. Usually, this quantity is very difficult to estimate from censored survival data with a limited follow-up period. The paper develops estimati...

journal_title：Statistics in medicine

authors： Titman AC

更新日期：2016-09-10 00:00:00

abstract：:A common but not necessarily logical requirement in drug development is that a 'limit of quantitation' be set for chemical assays and that observations that fall below the limit should not be treated as real data but should be labelled as below the limit and set aside for special treatment. We examine five of seven ap...

journal_title：Statistics in medicine

authors： Senn S,Holford N,Hockey H

更新日期：2012-12-30 00:00:00

abstract：:Recurrent event data occur in many clinical and observational studies, and in these situations, there may exist a terminal event such as death that is related to the recurrent event of interest. In addition, sometimes more than one type of recurrent events may occur, that is, one may encounter multivariate recurrent e...

journal_title：Statistics in medicine

authors： Zhu L,Sun J,Srivastava DK,Tong X,Leisenring W,Zhang H,Robison LL

更新日期：2011-11-10 00:00:00

abstract：:Assessment of quality of life is becoming standard in clinical trials. A popular method for measuring quality of life is with instruments which utilize multiple-item subscales, in which each item is scored on a Likert scale. Most statistical methods for the analysis of quality of life data in clinical trials do not ex...

journal_title：Statistics in medicine

authors： Douglas JA

更新日期：1999-11-15 00:00:00

abstract：:Many Americans rely on cardiac surgical procedures and devices such as pacemakers and thrombolytic catheters to treat or manage their cardiovascular diseases. However, the failure of these cardiac devices and procedures could have grave consequences. One reason cardiac devices tended to fail was due to physician error...

journal_title：Statistics in medicine

authors： Govindarajulu U,Bedi S,Kluger A,Resnic F

更新日期：2018-12-10 00:00:00

abstract：:A popular method to control multiplicity in confirmatory clinical trials is to use a so-called hierarchical, or fixed sequence, test procedure. This requires that the null hypotheses are ordered a priori, for example, in order of clinical importance. The procedure tests the hypotheses in this order using alpha-level t...

journal_title：Statistics in medicine

authors： Edwards D,Madsen J

更新日期：2007-12-10 00:00:00

abstract：:In this paper, we argue that causal effect models for realistic individualized treatment rules represent an attractive tool for analyzing sequentially randomized trials. Unlike a number of methods proposed previously, this approach does not rely on the assumption that intermediate outcomes are discrete or that models ...

journal_title：Statistics in medicine

authors： Bembom O,van der Laan MJ

更新日期：2008-08-30 00:00:00

abstract：:We consider recurrent events of the same type that occur during alternating restraint and non-restraint time periods. This research is motivated by a study on juvenile recidivism, where the probationers were followed for re-offenses during alternating placement periods and free-time periods. During the placement perio...

journal_title：Statistics in medicine

authors： Li X,Chen Y,Li R

更新日期：2017-02-20 00:00:00

abstract：:Differences between arm-based (AB) and contrast-based (CB) models for network meta-analysis (NMA) are controversial. We compare the CB model of Lu and Ades (2006), the AB model of Hong et al(2016), and two intermediate models, using hypothetical data and a selected real data set. Differences between models arise prima...

journal_title：Statistics in medicine

authors： White IR,Turner RM,Karahalios A,Salanti G

更新日期：2019-11-30 00:00:00

abstract：:This article introduces a global hypothesis test intended for studies with multiple endpoints. Our test makes use of a priori predictions about the direction of the result of each endpoint and we weight these predictions using the sample correlation matrix. The global alternative hypothesis concerns a parameter, ...

journal_title：Statistics in medicine

authors： Montgomery RN,Mahnken JD

更新日期：2020-12-10 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

authors： Cai JH,Song XY,Hser YI

更新日期：2010-08-15 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

abstract：:We consider a latent variable hazard model for clustered survival data where clusters are a random sample from an underlying population. We allow interactions between the random cluster effect and covariates. We use a maximum pseudo-likelihood estimator to estimate the mean hazard ratio parameters. We propose a bootst...

journal_title：Statistics in medicine

authors： Cai J,Zhou H,Davis CE

更新日期：1997-09-15 00:00:00

abstract：:Analyses to compare non-randomized groups are more and more common in both post hoc analyses of randomized clinical trials data and in analyses of long-term observational data. In such cases, it is quite likely that there are unknown or uncollected sources of heterogeneity in event rates. Research has shown that an un...

journal_title：Statistics in medicine

authors： Eberly LE

更新日期：2004-07-15 00:00:00

abstract：:The matched case-control designs are commonly used to control for potential confounding factors in genetic epidemiology studies especially epigenetic studies with DNA methylation. Compared with unmatched case-control studies with high-dimensional genomic or epigenetic data, there have been few variable selection metho...

journal_title：Statistics in medicine

authors： Sun H,Wang S

更新日期：2013-05-30 00:00:00

abstract：:Conventional seamless phase 2/3 design with fixed sample size determination (SSD) has gained its popularity in oncology drug development due to attractive features such as significantly shortening the development timeline, minimizing sample size, as well as early decision making. However, this design is not immune to ...

journal_title：Statistics in medicine

authors： Teng Z,Tian Y,Liu Y,Liu G

更新日期：2020-08-15 00:00:00