Exact approaches for testing hypotheses based on the intra-class kappa coefficient.

abstract：:A calibration line is used to define the relationship between a new clinical technique and a standard in vitro laboratory methodology. Discrimination intervals quantify the reliability of inverse estimates obtained from the calibration line. Applied to transcutaneous PCO2 monitoring, a new in vivo measurement, discrim...

journal_title：Statistics in medicine

authors： Kost GJ

更新日期：1986-07-01 00:00:00

abstract：:Increasing numbers of economic evaluations are conducted alongside randomised controlled trials. Such studies include factorial trials, which randomise patients to different levels of two or more factors and can therefore evaluate the effect of multiple treatments alone and in combination. Factorial trials can provide...

journal_title：Statistics in medicine

authors： Dakin H,Gray A

更新日期：2017-08-15 00:00:00

abstract：:We propose a new weighted hurdle regression method for modeling count data, with particular interest in modeling cardiovascular events in patients on dialysis. Cardiovascular disease remains one of the leading causes of hospitalization and death in this population. Our aim is to jointly model the relationship/associat...

journal_title：Statistics in medicine

authors： Sentürk D,Dalrymple LS,Mu Y,Nguyen DV

更新日期：2014-11-10 00:00:00

abstract：:Correlation is always a concern in the analysis of clustered data. One area of interest is to develop a general correlation modelling approach for high dimensional data with unbalanced hierarchical and heterogeneous data structures, e.g. multilevel data. Commonly used correlation structures might have limitation for s...

journal_title：Statistics in medicine

authors： Chao EC

更新日期：2006-07-30 00:00:00

abstract：:The need for resource-intensive laboratory assays to assess exposures in many epidemiologic studies provides ample motivation to consider study designs that incorporate pooled samples. In this paper, we consider the case in which specimens are combined for the purpose of determining the presence or absence of a pool-w...

journal_title：Statistics in medicine

authors： Lyles RH,Tang L,Lin J,Zhang Z,Mukherjee B

更新日期：2012-09-28 00:00:00

abstract：:The generalized estimating equations (GEE) approach is commonly used to model incomplete longitudinal binary data. When drop-outs are missing at random through dependence on observed responses (MAR), GEE may give biased parameter estimates in the model for the marginal means. A weighted estimating equations approach g...

journal_title：Statistics in medicine

authors： Preisser JS,Lohman KK,Rathouz PJ

更新日期：2002-10-30 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：:Assessing the calibration of methods for estimating the probability of the occurrence of a binary outcome is an important aspect of validating the performance of risk-prediction algorithms. Calibration commonly refers to the agreement between predicted and observed probabilities of the outcome. Graphical methods are a...

journal_title：Statistics in medicine

authors： Austin PC,Steyerberg EW

更新日期：2019-09-20 00:00:00

abstract：:Binary classification rules based on covariates typically depend on simple loss functions such as zero-one misclassification. Some cases may require more complex loss functions. For example, individual-level monitoring of HIV-infected individuals on antiretroviral therapy requires periodic assessment of treatment fail...

journal_title：Statistics in medicine

authors： Xu Y,Liu T,Daniels MJ,Kantor R,Mwangi A,Hogan JW

更新日期：2019-05-20 00:00:00

abstract：:Although population-based molecular association studies are becoming increasingly popular, methodology for the meta-analysis of these studies has been neglected, particularly with regard to two issues: testing Hardy-Weinberg equilibrium (HWE), and pooling results in a manner that reflects a biological model of gene ef...

journal_title：Statistics in medicine

authors： Thakkinstian A,McElduff P,D'Este C,Duffy D,Attia J

更新日期：2005-05-15 00:00:00

abstract：:In failure time studies involving a chronic disease such as cancer, several competing causes of mortality may be operating. Commonly, the conventional statistical technique of Kaplan-Meier, which is only meaningfully interpreted by assuming independence of failure types and the censoring mechanism, is employed in clin...

journal_title：Statistics in medicine

authors： Tai BC,Machin D,White I,Gebski V,EOI (The European Osteosarcoma Intergroup).

更新日期：2001-03-15 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：:Risk prediction models play an important role in prevention and treatment of several diseases. Models that are in clinical use are often refined and improved. In many instances, the most efficient way to improve a successful model is to identify subgroups for which there is a specific biological rationale for improvem...

journal_title：Statistics in medicine

authors： Biswas S,Arun B,Parmigiani G

更新日期：2014-05-20 00:00:00

abstract：:Missing values in the covariates are a widespread complication in the statistical inference of regression models. The maximum likelihood principle requires specification of the distribution of the covariates, at least in part. For categorical covariates, log-linear models can be used. Additionally, the missing at rand...

journal_title：Statistics in medicine

authors： Vach W,Blettner M

更新日期：1995-06-30 00:00:00

abstract：:The standard analysis of clinical trials stratified by centre is to include centres as fixed effects, but if many centres contribute small numbers of patients, this approach results in a loss of power. Assuming no treatment by centre interaction, we used simulation to examine power and coverage of confidence intervals...

journal_title：Statistics in medicine

authors： Pickering RM,Weatherall M

更新日期：2007-12-30 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

authors： Longini IM Jr,Byers RH,Hessol NA,Tan WY

更新日期：1992-04-01 00:00:00

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：:Combining multiple markers can improve classification accuracy compared with using a single marker. In practice, covariates associated with markers or disease outcome can affect the performance of a biomarker or biomarker combination in the population. The covariate-adjusted receiver operating characteristic (ROC) cur...

journal_title：Statistics in medicine

authors： Kim S,Huang Y

更新日期：2017-07-10 00:00:00

abstract：:Methods for addressing multiplicity in clinical trials have attracted much attention during the past 20 years. They include the investigation of new classes of multiple test procedures, such as fixed sequence, fallback and gatekeeping procedures. More recently, sequentially rejective graphical test procedures have bee...

journal_title：Statistics in medicine

authors： Maurer W,Bretz F

更新日期：2013-05-10 00:00:00

abstract：:The U.S. Food and Drug Administration (FDA) has proposed new regulations that address the 'prescribability' and 'switchability' of new formulations of already-approved drugs. These new criteria are known, respectively, as population and individual bioequivalence. Two methods have been proposed in the bioequivalence li...

journal_title：Statistics in medicine

authors： McNally RJ,Iyer H,Mathew T

更新日期：2003-01-15 00:00:00

abstract：:The use of logistic models for independent binary data has relied first on asymptotic theory and later on exact distributions for small samples. However, the use of logistic models for dependent analysis based on exact analysis is not as common. Moreover, attention is usually given to one-stage clustering. In this pap...

journal_title：Statistics in medicine

authors： Troxler S,Lalonde T,Wilson JR

更新日期：2011-04-15 00:00:00

abstract：:In clinical research, we are often interested in assessing how a biomarker changes with time, and whether it could be used as a surrogate marker when evaluating the efficacy of a new drug. However, when the longitudinal marker is correlated with survival, linear mixed models for longitudinal data may be inappropriate....

journal_title：Statistics in medicine

authors： Deslandes E,Chevret S

更新日期：2007-12-30 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：:In the comparison of two or more treatment groups to a control group, consider a study with non-decreasing repeated measurements of the same characteristic taken over a common set of time points for each subject. Based on the vector of possibly incomplete responses from each subject, this paper considers asymptoticall...

journal_title：Statistics in medicine

authors： Davis CS

更新日期：1996-12-15 00:00:00

abstract：:Longitudinal studies collect information on a sample of individuals which is followed over time to analyze the effects of individual and time-dependent characteristics on the observed response. These studies often suffer from attrition: individuals drop out of the study before its completion time and thus present inco...

journal_title：Statistics in medicine

authors： Alfò M,Maruotti A

更新日期：2009-08-30 00:00:00

abstract：:Appropriate quantification of added usefulness offered by new markers included in risk prediction algorithms is a problem of active research and debate. Standard methods, including statistical significance and c statistic are useful but not sufficient. Net reclassification improvement (NRI) offers a simple intuitive w...

journal_title：Statistics in medicine

authors： Pencina MJ,D'Agostino RB Sr,Steyerberg EW

更新日期：2011-01-15 00:00:00

abstract：:Previous work on the consequences of regression to the mean for the interpretation of responses to treatment is extended to the situation where the response measured is the proportional change in some variable. Methods for correcting for the bias are discussed. ...

journal_title：Statistics in medicine

authors： Curnow RN

更新日期：1987-03-01 00:00:00

abstract：:Equivalence trials aim to show that two treatments have equivalent therapeutic effects. The approach is to define, in advance, a range of equivalence -d to +d for the treatment difference such that any value in the range is clinically unimportant. If the confidence interval for the difference, calculated after the tri...

journal_title：Statistics in medicine

authors： Ebbutt AF,Frith L

更新日期：1998-08-15 00:00:00

abstract：:Piecewise constant incidence models were developed to estimate the force of infection in women from age- and time-specific antenatal or neonatal seroprevalence data. Differential inclusion of infected women in sero-surveys compared to uninfected women was taken into account, with respect to both changes in inclusion r...

journal_title：Statistics in medicine

authors： Ades AE,Medley GF

更新日期：1994-09-30 00:00:00

abstract：:With the increasing availability of detailed clinical information, there is optimism that treatment choices can be selectively directed to those individuals most likely to benefit. While standard clinical trials can establish whether a treatment appears to be effective on average, subsequent work is needed to determin...

journal_title：Statistics in medicine

authors： Sitlani CM,Heagerty PJ

更新日期：2014-07-30 00:00:00