The effect of unbalanced randomization on the progressively censored Savage test.

abstract：:In this paper, an approach to estimating the cumulative mean function for history process with time dependent covariates and right censored time-to-event variable is developed using the combined technique of joint modeling and inverse probability weighting method. The consistency of proposed estimator is derived. Theo...

journal_title：Statistics in medicine

authors： Deng D

更新日期：2016-11-10 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：:We study the group bridge and the adaptive group bridge penalties for competing risks quantile regression with group variables. While the group bridge consistently identifies nonzero group variables, the adaptive group bridge consistently selects variables not only at group level but also at within-group level. We all...

journal_title：Statistics in medicine

authors： Ahn KW,Kim S

更新日期：2018-04-30 00:00:00

abstract：BACKGROUND:The need to deliver interventions targeting multiple diseases in a cost-effective manner calls for integrated disease control efforts. Consequently, maps are required that show where the risk of co-infection is particularly high. Co-infection risk is preferably estimated via Bayesian geostatistical multinomi...

journal_title：Statistics in medicine

authors： Schur N,Gosoniu L,Raso G,Utzinger J,Vounatsou P

更新日期：2011-06-30 00:00:00

abstract：:A common problem encountered in many medical applications is the comparison of survival curves. Often, rather than comparison of the entire survival curves, interest is focused on the comparison at a fixed point in time. In most cases, the naive test based on a difference in the estimates of survival is used for this ...

journal_title：Statistics in medicine

authors： Klein JP,Logan B,Harhoff M,Andersen PK

更新日期：2007-10-30 00:00:00

abstract：:Between-community variance or community-by-time variance is one of the key factors driving the cost of conducting group randomized trials, which are often very expensive. We investigated empirically whether between-community variance could be reduced by controlling individual- and/or community-level covariates and ide...

journal_title：Statistics in medicine

authors： Feng Z,Diehr P,Yasui Y,Evans B,Beresford S,Koepsell TD

更新日期：1999-03-15 00:00:00

abstract：:Many observational studies adopt what we call retrospective convenience sampling (RCS). With the sample size in each arm prespecified, RCS randomly selects subjects from the treatment-inclined subpopulation into the treatment arm and those from the control-inclined into the control arm. Samples in each arm are represe...

journal_title：Statistics in medicine

authors： Hu Z,Qin J

更新日期：2018-05-20 00:00:00

abstract：:It is naive and incorrect to use the proportions of successful operations to compare the performance of surgeons because the patients' risk profiles are different. In this paper, we explore the use of risk-adjusted procedures to compare the performance of surgeons. One such risk-adjusted statistic is the standardized ...

journal_title：Statistics in medicine

authors： Tang X,Gan FF

更新日期：2017-07-20 00:00:00

abstract：:The problem for assessing biosimilarity and drug interchangeability of follow-on biologics (biosimilar products) is studied. Unlike the generic products, the development of biosimilar products is much more complicated because of fundamental differences in functional structures and manufacturing processes. As a result,...

journal_title：Statistics in medicine

authors： Chow SC,Wang J,Endrenyi L,Lachenbruch PA

更新日期：2013-02-10 00:00:00

abstract：:Quantifying socioeconomic disparities and understanding the roots of inequalities are growing topics in cancer research. However, socioeconomic differences are challenging to investigate mainly due to the lack of accurate data at individual-level, while aggregate indicators are only partially informative. We implement...

journal_title：Statistics in medicine

authors： Mezzetti M,Palli D,Dominici F

更新日期：2020-01-15 00:00:00

abstract：:Frailty models are encountered in many medical applications, yet little research has been devoted to develop measures that quantify the predictive ability of these models. In this paper, we elaborate on the concept of the concordance probability to clustered data, resulting in an 'Overall Conditional C-index' or bfC(O...

journal_title：Statistics in medicine

authors： Van Oirbeek R,Lesaffre E

更新日期：2010-12-30 00:00:00

abstract：:One Sentence Summary: A Bayesian repeated measures model based on quantitative muscle strength data from a prospective Natural History Study was developed to determine disease progression and design clinical trials for GNE myopathy, a rare and slowly progressive muscle disease. GNE myopathy is a rare muscle disease ch...

journal_title：Statistics in medicine

authors： Quintana M,Shrader J,Slota C,Joe G,McKew JC,Fitzgerald M,Gahl WA,Berry S,Carrillo N

更新日期：2019-04-15 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：:Subjects in randomized controlled trials do not always comply to the treatment condition they have been assigned to. This may cause the estimated effect of the intervention to be biased and also affect efficiency, coverage of confidence intervals, and statistical power. In cluster randomized trials non-compliance may ...

journal_title：Statistics in medicine

authors： Moerbeek M,Schie SV

更新日期：2019-11-20 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：:Sensible plans for health-care needs and determination of priorities for expenditure require regular assessment of trends in HIV incidences. In particular, trends in the relative HIV incidences of different risk categories are useful when assessing whether current control strategies are working equally well for all ri...

journal_title：Statistics in medicine

authors： Becker NG,Cui JS

更新日期：1996-08-30 00:00:00

abstract：:Two features commonly exhibited by randomized trials of health promotion interventions are cluster randomization and stratification. Ignoring correlations between individuals within clusters can lead to an inflated type I error rate and hence a P-value which overstates the significance of the result. This paper compar...

journal_title：Statistics in medicine

authors： Dobbins TA,Simpson JM

更新日期：2002-12-30 00:00:00

abstract：:Given N points or events occurring according to some probability distribution in the unit interval (0, 1), the simple scan statistic is defined to be the maximum number of points in any sub-interval of length d. In many areas, as in epidemiology, it is used to test the null hypothesis that the events are random, again...

journal_title：Statistics in medicine

authors： Nagarwalla N

更新日期：1996-04-15 00:00:00

abstract：:Population heterogeneity is frequently observed among patients' treatment responses in clinical trials because of various factors such as clinical background, environmental, and genetic factors. Different subpopulations defined by those baseline factors can lead to differences in the benefit or safety profile of a the...

journal_title：Statistics in medicine

authors： Chiu YD,Koenig F,Posch M,Jaki T

更新日期：2018-12-20 00:00:00

abstract：:Biomedical studies often measure variables with error. Examples in the literature include investigation of the association between the change in some outcome variable (blood pressure, cholesterol level etc.) and a set of explanatory variables (age, smoking status etc.). Typically, one fits linear regression models to ...

journal_title：Statistics in medicine

authors： Yanez ND 3rd,Kronmal RA,Shemanski LR

更新日期：1998-11-30 00:00:00

abstract：:This paper describes compliance with the completion of a quality of life questionnaire in the Breast Cancer Prevention Trial, a large multi-centre randomized trial that is studying the efficacy of Tamoxifen in preventing breast cancer. In the first 4875 women enrolled in the control arm of the study, there was a very ...

journal_title：Statistics in medicine

authors： Ganz PA,Day R,Costantino J

更新日期：1998-03-15 00:00:00

abstract：:This article deals with determination of a sample size that guarantees the success of a trial. We follow a Bayesian approach and we say an experiment is successful if it yields a large posterior probability that an unknown parameter of interest (an unknown treatment effect or an effects-difference) is greater than a c...

journal_title：Statistics in medicine

authors： Brutti P,De Santis F,Gubbiotti S

更新日期：2008-06-15 00:00:00

abstract：:We discuss the use of the trichotomous logistic model to discriminate between patients with gastrointestinal (GI) cancer, patients with benign GI disease and 'normal' subjects, using symptoms and the concentrations of some serum proteins that are potentially indicative of malignancy as covariates. A parsimonious model...

journal_title：Statistics in medicine

authors： Marshall RJ,Chisholm EM

更新日期：1985-07-01 00:00:00

abstract：:Interval-censored data are commonly found in studies of diseases that progress without symptoms, which require clinical evaluation for detection. Several techniques have been suggested with independent assumption. However, the assumption will not be valid if observations come from clusters. Furthermore, when the clust...

journal_title：Statistics in medicine

authors： Kim YJ

更新日期：2010-12-10 00:00:00

abstract：:A Non-Parametric Maximum Likelihood approach to the estimation of relative risks in the context of disease mapping is discussed and a NPML approximation to conditional autoregressive models is proposed. NPML estimates have been compared to other proposed solutions (Maximum Likelihood via Monte Carlo Scoring, Hierarchi...

journal_title：Statistics in medicine

authors： Biggeri A,Marchi M,Lagazio C,Martuzzi M,Böhning D

更新日期：2000-09-15 00:00:00

abstract：:The most popular model used for survival analysis is the proportional hazards regression model proposed by Cox. This is mainly due to its exceptional simplicity. Nevertheless the fundamental assumption of the Cox model is the proportionality of the hazards. For many applications, however, this assumption is doubtful. ...

journal_title：Statistics in medicine

authors： Berger U,Schäfer J,Ulm K

更新日期：2003-04-15 00:00:00

abstract：:Patients who switch treatment groups in randomized clinical trials can cause problems in the interpretation of the results. Although the intention-to-treat method is recognized as being the most reliable analysis, it may result in an underestimate of the treatment effect if there have been patients who switch treatmen...

journal_title：Statistics in medicine

authors： Law MG,Kaldor JM

更新日期：1996-10-15 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：:When investigating health disparities, it can be of interest to explore whether adjustment for socioeconomic factors at the neighborhood level can account for, or even reverse, an unadjusted difference. Recently, we proposed new methods to adjust the effect of an individual-level covariate for confounding by unmeasure...

journal_title：Statistics in medicine

authors： Brumback BA,Zheng HW,Dailey AB

更新日期：2013-04-15 00:00:00

abstract：:In genetic association studies, it is typically thought that genetic variants and environmental variables jointly will explain more of the inheritance of a phenotype than either of these two components separately. Traditional methods to identify gene-environment interactions typically consider only one measured enviro...

journal_title：Statistics in medicine

authors： Pashova H,LeBlanc M,Kooperberg C

更新日期：2013-01-30 00:00:00