A standardization method to adjust for the effect of patient selection in phase II clinical trials.

abstract：:Correlated response data arise often in biomedical studies. The generalized estimation equation (GEE) approach is widely used in regression analysis for such data. However, there are few methods available to check the adequacy of regression models in GEE. In this paper, a graphical method is proposed based on Cook and...

journal_title：Statistics in medicine

authors： Pan W,Connett JE,Porzio GC,Weisberg S

更新日期：2001-10-15 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：: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：: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

authors： Rubin G,Umbach D,Shyu SF,Castillo-Chavez C

更新日期：1992-09-15 00:00:00

abstract：:In this paper statistical methods are proposed to estimate the distribution of a CD4 T-cell number at the time of a clinical AIDS endpoint from serial measurements of CD4 T-cell values in a cohort study. The statistical formulation of the problem is that of survival analysis with interval censored data, but in which t...

journal_title：Statistics in medicine

authors： Taylor JM,Kim DK

更新日期：1994-10-15 00:00:00

abstract：:The Jimma Infant Survival Differential Longitudinal Study is an Ethiopian study, set up to establish risk factors affecting infant survival and to investigate socio-economic, maternal and infant-rearing factors that contribute most to the child's early survival. Here, a subgroup of about 1500 children born in Jimma to...

journal_title：Statistics in medicine

authors： Lesaffre E,Asefa M,Verbeke G

更新日期：1999-04-15 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：:In biomedical research such as the development of vaccines for infectious diseases or cancer, study outcomes measured by an assay or device are often collected from multiple sources or laboratories. Measurement error that may vary between laboratories needs to be adjusted for when combining samples across data sources...

journal_title：Statistics in medicine

authors： Huang Y,Huang Y,Moodie Z,Li S,Self S

更新日期：2012-12-10 00:00:00

abstract：:Tree-based methods have become popular for analyzing complex data structures where the primary goal is risk stratification of patients. Ensemble techniques improve the accuracy in prediction and address the instability in a single tree by growing an ensemble of trees and aggregating. However, in the process, individua...

journal_title：Statistics in medicine

authors： Banerjee M,Ding Y,Noone AM

更新日期：2012-07-10 00:00:00

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 o...

journal_title：Statistics in medicine

authors： Agresti A

更新日期：1989-10-01 00:00:00

abstract：:The publication of Fisher's correspondence on statistics has shed new light on his views on randomization. Quotations from this correspondence and from other works of Fisher are used to illustrate the role of randomization in clinical trials. It is concluded that Fisher's views not only are coherent but, despite havin...

journal_title：Statistics in medicine

authors： Senn S

更新日期：1994-02-15 00:00:00

abstract：:Correct specification of the inverse probability weighting (IPW) model is necessary for consistent inference from a marginal structural Cox model (MSCM). In practical applications, researchers are typically unaware of the true specification of the weight model. Nonetheless, IPWs are commonly estimated using parametric...

journal_title：Statistics in medicine

authors： Karim ME,Platt RW,BeAMS study group.

更新日期：2017-06-15 00:00:00

abstract：:Multivariate outcomes measured longitudinally over time are common in medicine, public health, psychology and sociology. The typical (saturated) longitudinal multivariate regression model has a separate set of regression coefficients for each outcome. However, multivariate outcomes are often quite similar and many out...

journal_title：Statistics in medicine

authors： Jia J,Weiss RE

更新日期：2009-06-15 00:00:00

abstract：:We provide a Bayesian analysis of data categorized into two levels of age (younger than 50 years, at least 50 years) and three levels of bone mineral density (normal, osteopenia, osteoporosis) for white females at least 20 years old in the third National Health and Nutrition Examination Survey. For the sample, the age...

journal_title：Statistics in medicine

authors： Nandram B,Liu N,Choi JW,Cox L

更新日期：2005-04-15 00:00:00

abstract：:A new goodness-of-fit test for the logistic regression model is proposed. It exploits the property of this model that when it is correct, i.e. not misspecified, the parameter estimates are (asymptotically) invariant under reweighting the observations by weights wi that are a function of the binary (0/1) outcomes yi. M...

journal_title：Statistics in medicine

authors： Nagelkerke N,Smits J,le Cessie S,van Houwelingen H

更新日期：2005-01-15 00:00:00

abstract：:Propensity score analysis is widely used in observational studies to adjust for confounding and estimate the causal effect of a treatment on the outcome. When the outcome is survival time, there are special considerations on the definition of the causal estimand, point, and variance estimation that have not been thoro...

journal_title：Statistics in medicine

authors： Mao H,Li L,Yang W,Shen Y

更新日期：2018-11-20 00:00:00

abstract：:When data are dichotomous, this paper notes the utility of inverse sampling in establishing equivalence with respect to the risk ratio. This paper develops an exact equivalence test that accounts for the risk ratio under inverse sampling and further discusses the relationship between the exact equivalence test and the...

journal_title：Statistics in medicine

authors： Lui KJ

更新日期：1997-08-15 00:00:00

abstract：:We extend the shared frailty model of recurrent events and a dependent terminal event to allow for a nonparametric covariate function. We include a Gaussian random effect (frailty) in the intensity functions of both the recurrent and terminal events to capture correlation between the two processes. We employ the penal...

journal_title：Statistics in medicine

authors： Zhangsheng Y,Liu L

更新日期：2011-09-30 00:00:00

abstract：:This paper investigates the design and analysis of dose-finding trials with two agents. The set of doses for each agent is fixed in advance. The goal of the trial is to find the set of dose combinations with probability of toxicity closest to a pre-specified value. For each of the two agents we assume that the probabi...

journal_title：Statistics in medicine

authors： Ivanova A,Wang K

更新日期：2004-06-30 00:00:00

abstract：:The mutation and natural selection phenomenon can and often does cause the failure of antimicrobial, herbicidal, pesticide and cancer treatments selection pressures. This phenomenon operates in a mathematically predictable behavior, which when understood leads to approaches to reduce and prevent the failure of the use...

journal_title：Statistics in medicine

authors： Kleinman A

更新日期：2014-12-20 00:00:00

abstract：:Misclassification introduces errors in categorical variables. This paper presents a review of methods for misclassified categorical data in epidemiology. Different sampling schemes for a 2 x 2 x 2 table and methods of analyses will be discussed first. A misclassification matrix is defined, and the usual misclassificat...

journal_title：Statistics in medicine

authors： Chen TT

更新日期：1989-09-01 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

authors： Kennedy EH,Taylor JM,Schaubel DE,Williams S

更新日期：2010-11-10 00:00:00

abstract：:Proportional hazards (or Cox) regression is a popular method for modelling the effects of prognostic factors on survival. Use of cubic spline functions to model time-by-covariate interactions in Cox regression allows investigation of the shape of a possible covariate-time dependence without having to specify a specifi...

journal_title：Statistics in medicine

authors： Hess KR

更新日期：1994-05-30 00:00:00

abstract：:Outcome-dependent sampling (ODS) scheme is a cost-effective sampling scheme where one observes the exposure with a probability that depends on the outcome. The well-known such design is the case-control design for binary response, the case-cohort design for the failure time data, and the general ODS design for a conti...

journal_title：Statistics in medicine

authors： Lu TS,Longnecker MP,Zhou H

更新日期：2017-03-15 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

authors： Austin PC,Steyerberg EW

更新日期：2013-02-20 00:00:00

abstract：:Bioequivalence or interaction trials are commonly studied in crossover design and can be analysed by nonlinear mixed effects models as an alternative to noncompartmental approach. We propose an extension of the population Fisher information matrix in nonlinear mixed effects models to design crossover pharmacokinetic t...

journal_title：Statistics in medicine

authors： Nguyen TT,Bazzoli C,Mentré F

更新日期：2012-05-20 00:00:00

abstract：:The proposed guidelines for the assessment of the effect of new pharmaceutical agents on the QT interval (beginning of QRS complex to end of T wave on the electrocardiogram) are based on the maximum of a series over time of simple one-sided 95 per cent upper confidence bounds. This procedure is typically very conserva...

journal_title：Statistics in medicine

authors： Boos DD,Hoffman D,Kringle R,Zhang J

更新日期：2007-09-10 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

authors： Lachos VH,A Matos L,Castro LM,Chen MH

更新日期：2019-03-15 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：: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

authors： Greenland S

更新日期：1987-09-01 00:00:00