Sample size calculation for clinical trials with correlated count measurements based on the negative binomial distribution.

abstract：:Various R(2) statistics have been proposed for logistic regression to quantify the extent to which the binary response can be predicted by a given logistic regression model and covariates. We study the asymptotic properties of three popular variance-based R(2) statistics. We find that two variance-based R(2) statistic...

journal_title：Statistics in medicine

authors： Hu B,Palta M,Shao J

更新日期：2006-04-30 00:00:00

abstract：:This paper concerns the statistical analysis of certain binary data arising in molecular studies of cancer. In allelic-loss experiments, tumour cell genomes are analysed at informative molecular marker loci to identify deleted chromosomal regions. The resulting binary data are used to infer properties of putative supp...

journal_title：Statistics in medicine

authors： Newton MA,Gould MN,Reznikoff CA,Haag JD

更新日期：1998-07-15 00:00:00

abstract：:R2 has been criticized as a measure of model performance when predicting a dichotomous outcome, both because its value is often low and because it is sensitive to the prevalence of the event of interest. The C statistic is more widely used to measure model performance in a 0/1 setting. We use a simple parametric famil...

journal_title：Statistics in medicine

authors： Ash A,Shwartz M

更新日期：1999-02-28 00:00:00

abstract：:We consider statistical procedures for hypothesis testing of real valued functionals of matched pairs with missing values. In order to improve the accuracy of existing methods, we propose a novel multiplication combination procedure. Dividing the observed data into dependent (completely observed) pairs and independent...

journal_title：Statistics in medicine

authors： Amro L,Konietschke F,Pauly M

更新日期：2019-07-30 00:00:00

abstract：:This paper discusses and compares several estimators of mean rate of change in unbalanced longitudinal data based on a model with randomly distributed regression coefficients across individuals. The estimators are unweighted and weighted means of these coefficients. The paper also evaluates commonly used variance esti...

journal_title：Statistics in medicine

authors： Palta M,Cook T

更新日期：1987-07-01 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：:In this paper, we investigate the impact of time-invariant covariates when fitting transition mixed models. This is carried out by emphasizing on the role of baseline responses on the estimation process. Transition models are allowed for two cases of exogenous and endogenous baseline responses. We illustrate these con...

journal_title：Statistics in medicine

authors： Rikhtehgaran R,Kazemi I,Verbeke G

更新日期：2014-11-30 00:00:00

abstract：:We consider Cox proportional hazards regression when the covariate vector includes error-prone discrete covariates along with error-free covariates, which may be discrete or continuous. The misclassification in the discrete error-prone covariates is allowed to be of any specified form. Building on the work of Nakamura...

journal_title：Statistics in medicine

authors： Zucker DM,Spiegelman D

更新日期：2008-05-20 00:00:00

abstract：:Correlation is inherent in longitudinal studies due to the repeated measurements on subjects, as well as due to time-dependent covariates in the study. In the National Longitudinal Study of Adolescent to Adult Health (Add Health), data were repeatedly collected on children in grades 7-12 across four waves. Thus, obser...

journal_title：Statistics in medicine

authors： Irimata KM,Broatch J,Wilson JR

更新日期：2019-05-30 00:00:00

abstract：:This paper reviews Bayesian strategies for monitoring clinical trial data. It focuses on a Bayesian stochastic curtailment method based on the predictive probability of observing a clinically significant outcome at the scheduled end of the study given the observed data. The proposed method is applied to derive efficac...

journal_title：Statistics in medicine

authors： Dmitrienko A,Wang MD

更新日期：2006-07-15 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：:Health surveillance involves collecting public health data on chronic and infectious diseases to detect changes in disease incidence rates in order to improve public health. Timely detection of disease clusters is essential in prospective public health surveillance. Most existing health surveillance research is based ...

journal_title：Statistics in medicine

authors： Jiang W,Han SW,Tsui KL,Woodall WH

更新日期：2011-02-28 00:00:00

abstract：:This paper presents a statistically optimal exact hypothesis testing procedure for detecting changes in sales adjusted adverse drug reaction (ADR) rates between historical and current periods, with a computer program that implements this test appended. We provide discussions and illustrations on how to monitor ADR rat...

journal_title：Statistics in medicine

authors： Norwood PK,Sampson AR

更新日期：1988-10-01 00:00:00

abstract：:Although hypertension is regarded as a causal factor for coronary heart disease (CHD) a reduction in the risk of CHD as a result of lowering blood pressure in mild hypertension could not be demonstrated. This conclusion is based on an overview analysis of all published randomized trials in mild hypertension, including...

journal_title：Statistics in medicine

authors： Holme I

更新日期：1988-11-01 00:00:00

abstract：:The recent revision of the Declaration of Helsinki and the existence of many new therapies that affect survival or serious morbidity, and that therefore cannot be denied patients, have generated increased interest in active-control trials, particularly those intended to show equivalence or non-inferiority to the activ...

journal_title：Statistics in medicine

authors： Rothmann M,Li N,Chen G,Chi GY,Temple R,Tsou HH

更新日期：2003-01-30 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：:Assessment of equivalence or non-inferiority in accuracy between two diagnostic procedures often involves comparisons of paired areas under the receiver operating characteristic (ROC) curves. With some pre-specified clinically meaningful limits, the current approach to evaluating equivalence is to perform the two one-...

journal_title：Statistics in medicine

authors： Liu JP,Ma MC,Wu CY,Tai JY

更新日期：2006-04-15 00:00:00

abstract：:Multivariate finite mixture models have been applied to the identification of dietary patterns. These models are known to have many parameters, and consequently large samples are usually required. We present a special case of a multivariate mixture model that reduces the number of parameters to be estimated and seems ...

journal_title：Statistics in medicine

authors： Rita Gaio A,Costa JP,Santos AC,Ramos E,Lopes C

更新日期：2012-08-30 00:00:00

abstract：:Results from an analysis of traffic accidents from a study of the police records of four police stations in the Bangkok metropolis are presented. The main emphasis in this study was put on the development of a measure for traffic accident density. The traffic flow was estimated at the various study locations by traine...

journal_title：Statistics in medicine

authors： Ayuthya RS,Böhning D

更新日期：1995-11-15 00:00:00

abstract：:In recent years, quality control charts have been increasingly applied in the healthcare environment, for example, to monitor surgical performance. Risk-adjusted cumulative (CUSUM) charts that utilize risk scores like the Parsonnet score to estimate the probability of death of a patient from an operation turn out to b...

journal_title：Statistics in medicine

authors： Knoth S,Wittenberg P,Gan FF

更新日期：2019-05-30 00:00:00

abstract：:The Spearman (rho(s)) and Kendall (tau) rank correlation coefficient are routinely used as measures of association between non-normally distributed random variables. However, confidence limits for rho(s) are only available under the assumption of bivariate normality and for tau under the assumption of asymptotic norma...

journal_title：Statistics in medicine

authors： Rosner B,Glynn RJ

更新日期：2007-02-10 00:00:00

abstract：:Providing personalized treatments designed to maximize benefits and minimizing harms is of tremendous current medical interest. One problem in this area is the evaluation of the interaction between the treatment and other predictor variables. Treatment effects in subgroups having the same direction but different magni...

journal_title：Statistics in medicine

authors： Chen W,Ghosh D,Raghunathan TE,Norkin M,Sargent DJ,Bepler G

更新日期：2012-12-10 00:00:00

abstract：:A few large multi-centre male-only heart trials done in the 1970s and 1980s have been seen as ill-conceived because they did not include females. The purpose here is to revisit two of those trials and to consider consequences in terms of cost and power had they been designed to include females. ...

journal_title：Statistics in medicine

authors： Meinert CL

更新日期：1999-02-15 00:00:00

abstract：:The randomized clinical trial, LU19, conducted by the Medical Research Council Lung Cancer Working Party, was designed to compare ACE (doxorubicin, cyclophosphamide and etoposide) chemotherapy plus G-CSF (granulocyte colony-stimulating factor) at 2-week intervals versus ACE chemotherapy alone at standard 3-week interv...

journal_title：Statistics in medicine

authors： Qian W,Parmar MK,Sambrook RJ,Fayers PM,Girling DJ,Stephens RJ

更新日期：2000-10-15 00:00:00

abstract：:A three-component, competing-risk mortality model, developed for animal survival data, fits human life table data for all ages over a range of mean life spans from 16 to 74 years. The competing risks are a novel exponentially-decreasing hazard, dominant during immaturity; a constant hazard, dominant during adulthood; ...

journal_title：Statistics in medicine

authors： Siler W

更新日期：1983-07-01 00:00:00

abstract：:In this paper we examine the efficiency of a generalization of the traditional normal linear (LDA) or quadratic (QDA) discriminant analysis. This procedure (the generalized discriminant analysis, GDA) replaces each normal density used in the traditional classification rule by a Fourier series density estimator which '...

journal_title：Statistics in medicine

authors： Odom-Maryon T,Langholz B,Niland J,Azen S

更新日期：1991-03-01 00:00:00

abstract：:The two tailed Fisher's exact P value is extremely sensitive to small perturbations in 2 x 2 contingency tables. An example indicates that a 1 per cent increase in the denominator of one treatment group results in a 32 per cent drop in the exact P value, but a mere 0.1 per cent decrease in the treatment success rate. ...

journal_title：Statistics in medicine

authors： Dupont WD

更新日期：1986-11-01 00:00:00

abstract：:The explanation of heterogeneity plays an important role in meta-analysis. The random effects meta-regression model allows the inclusion of trial-specific covariates which may explain a part of the heterogeneity. We examine the commonly used tests on the parameters in the random effects meta-regression with one covari...

journal_title：Statistics in medicine

authors： Knapp G,Hartung J

更新日期：2003-09-15 00:00:00

abstract：:Sam Greenhouse joined the Census Bureau as a clerk at an interesting time period for the agency. The first use of sampling in the decennial census occurred in 1940. There was a major expansion of the amount of data collected. The organization of the Census Bureau underwent radical changes, including the growth of the ...

journal_title：Statistics in medicine

authors： Keller J,Clark CZ

更新日期：2003-11-15 00:00:00

abstract：:We examine the properties of several tests for goodness-of-fit for multinomial logistic regression. One test is based on a strategy of sorting the observations according to the complement of the estimated probability for the reference outcome category and then grouping the subjects into g equal-sized groups. A g x c c...

journal_title：Statistics in medicine

authors： Fagerland MW,Hosmer DW,Bofin AM

更新日期：2008-09-20 00:00:00