Performance of analytical methods for overdispersed counts in cluster randomized trials: sample size, degree of clustering and imbalance.

abstract：:Statistical methods for testing and interval estimation of the ratio of marginal probabilities in the matched-pair setting are considered in this paper. We are especially interested in the situation where the null value is not one, as in one-sided equivalence trials. We propose a Fieller-type statistic based on constr...

journal_title：Statistics in medicine

authors： Nam JM,Blackwelder WC

更新日期：2002-03-15 00:00:00

abstract：:Delay in the outcome variable is challenging for outcome-adaptive randomization, as it creates a lag between the number of subjects accrued and the information known at the time of the analysis. Motivated by a real-life pediatric ulcerative colitis trial, we consider a case where a short-term predictor is available fo...

journal_title：Statistics in medicine

authors： Kim MO,Liu C,Hu F,Lee JJ

更新日期：2014-10-15 00:00:00

abstract：:We consider a general model for anomaly detection in a longitudinal cohort mortality pattern based on logistic joinpoint regression with unknown joinpoints. We discuss backward and forward sequential procedures for selecting both the locations and the number of joinpoints. Estimation of the model parameters and the se...

journal_title：Statistics in medicine

authors： Czajkowski M,Gill R,Rempala G

更新日期：2008-04-30 00:00:00

abstract：:Many critical questions in medicine require the analysis of complex multivariate data, often from large data sets describing numerous variables for numerous subjects. In this paper, we describe CoPlot, a tool for visualizing multivariate data in medicine. CoPlot is an adaptation of multidimensional scaling (MDS) that ...

journal_title：Statistics in medicine

authors： Bravata DM,Shojania KG,Olkin I,Raveh A

更新日期：2008-05-30 00:00:00

abstract：:For genome-wide association studies, we propose a new method for identifying significant biological pathways. In this approach, we aggregate data across single-nucleotide polymorphisms to obtain summary measures at the gene level. We then use a hierarchical Bayesian model, which takes the gene-level summary measures a...

journal_title：Statistics in medicine

authors： Shahbaba B,Shachaf CM,Yu Z

更新日期：2012-05-10 00:00:00

abstract：:The FDA Guidance, while highly appropriate for industry sponsored trials, need not be imposed on publicly (e.g. NIH) financed clinical trials. While the potential for conflicts of interest exist in the latter, they are in general manageable and pose an acceptable low risk of threatening the integrity of a study. Howev...

journal_title：Statistics in medicine

authors： Lachin JM

更新日期：2004-05-30 00:00:00

abstract：:The primary purpose of a disease surveillance system is to provide data for the detection of changes in the incidence of the disease. Methods for the analysis of data from surveillance systems are reviewed. A new procedure is proposed for use when the system includes geographically dispersed reporting units, such as h...

journal_title：Statistics in medicine

authors： Raubertas RF

更新日期：1989-03-01 00:00:00

abstract：:Using both simulated and real datasets, we compared two approaches for estimating absolute risk from nested case-control (NCC) data and demonstrated the feasibility of using the NCC design for estimating absolute risk. In contrast to previously published results, we successfully demonstrated not only that data from a ...

journal_title：Statistics in medicine

authors： Salim A,Delcoigne B,Villaflores K,Koh WP,Yuan JM,van Dam RM,Reilly M

更新日期：2017-02-10 00:00:00

abstract：:Patient compliance (adherence) with prescribed medication is often erratic, while clinical outcomes are causally linked to actual, rather than nominal medication dosage. We propose here a hierarchical Markov model for patient compliance. At the first stage, conditional upon individual random effects and a set of indiv...

journal_title：Statistics in medicine

authors： Girard P,Blaschke TF,Kastrissios H,Sheiner LB

更新日期：1998-10-30 00:00:00

abstract：:The objective of this report is to provide a basis to inform decisions about priorities for developing statistical research initiatives in the field of public health surveillance for emerging threats. Rapid information system advances have created a vast opportunity of secondary data sources for information to enhance...

journal_title：Statistics in medicine

authors： Rolka H,Burkom H,Cooper GF,Kulldorff M,Madigan D,Wong WK

更新日期：2007-04-15 00:00:00

abstract：:In psychiatry, clinicians use criteria sets from the Diagnostic and Statistical Manual of Mental Disorders to diagnose mental disorders. Most criteria sets have several symptom domains, and in order to be diagnosed, an individual must meet the minimum number of symptoms required by each domain. Some efforts are now fo...

journal_title：Statistics in medicine

authors： Mauro C,Shear MK,Wang Y

更新日期：2019-07-20 00:00:00

abstract：:Public health interventions are often designed to target communities defined either geographically (e.g. cities, counties) or socially (e.g. schools or workplaces). The group randomized trial (GRT) is regarded as the gold standard for evaluating these interventions. However, community leaders may object to randomizati...

journal_title：Statistics in medicine

authors： Pennell ML,Hade EM,Murray DM,Rhoda DA

更新日期：2011-07-10 00:00:00

abstract：:In this commentary, we revisit Sir Austin Bradford Hill's seminal Alfred Watson Memorial Lecture in 1962 through the eyes of two practicing biostatisticians of the current era. We summarize some eternal takeaway messages from Hill's lecture regarding observations and experiments translated through the modern lexicon o...

journal_title：Statistics in medicine

authors： Dempsey W,Mukherjee B

更新日期：2021-01-15 00:00:00

abstract：:Diseases can be interconnected. In the recent years, there has been a surge of multidisease studies. Among them, HDN (human disease network) analysis takes a system perspective, examines the interconnections among diseases along with their individual properties, and has demonstrated great potential. Most of the existi...

journal_title：Statistics in medicine

authors： Ma C,Li Y,Shia B,Ma S

更新日期：2020-04-30 00:00:00

abstract：:In this paper, we discuss family-based association test (FBATs) relating genetic data to survival and time-to-onset data. We show how the standard logrank and Wilcoxon statistics can be used with family data to develop tests of association. We prove that the FBAT-logrank approach can be identical to the proportional h...

journal_title：Statistics in medicine

authors： Lange C,Blacker D,Laird NM

更新日期：2004-01-30 00:00:00

abstract：:Quality of life (QOL) assessment is a key component of many clinical studies and frequently requires the use of single global summary measures that capture the overall balance of findings from a potentially wide-ranging assessment of QOL issues. We propose and evaluate an irregular multilevel latent variable model sui...

journal_title：Statistics in medicine

authors： Kifley A,Heller GZ,Beath KJ,Bulger D,Ma J,Gebski V

更新日期：2012-05-20 00:00:00

abstract：:Longitudinal studies with repeated measures are often subject to non-response. Methods currently employed to alleviate the difficulties caused by missing data are typically unsatisfactory, especially when the cause of the missingness is related to the outcomes. We present an approach for incomplete categorical data in...

journal_title：Statistics in medicine

authors： West CP,Dawson JD

更新日期：2002-01-30 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：:Suppression of premature ventricular contractions (PVCs) is one of the goals of antiarrhythmic therapy. In a clinical trial, however, it may be difficult to distinguish antiarrhythmic drug effect from spontaneous variation in PVCs. We propose the application of linear regression to PVC histories to ascertain drug effe...

journal_title：Statistics in medicine

authors： Berry DA,Fox TL

更新日期：1983-07-01 00:00:00

abstract：:Models for infant growth have usually been based on parametric forms, commonly an exponential or similar model, which have been shown to fit poorly especially during the first year of life. An alternative approach is to use a non-parametric model, based on a shape invariant model (SIM), where a single function is tran...

journal_title：Statistics in medicine

authors： Beath KJ

更新日期：2007-05-30 00:00:00

abstract：:Conditional power (CP) is the probability that the final study result will be statistically significant, given the data observed thus far and a specific assumption about the pattern of the data to be observed in the remainder of the study, such as assuming the original design effect, or the effect estimated from the c...

journal_title：Statistics in medicine

authors： Lachin JM

更新日期：2005-09-30 00:00:00

abstract：:Estimates of relative efficacy between alternative treatments are crucial for decision making in health care. Bayesian mixed treatment comparison models provide a powerful methodology to obtain such estimates when head-to-head evidence is not available or insufficient. In recent years, this methodology has become wide...

journal_title：Statistics in medicine

authors： Schmitz S,Adams R,Walsh C

更新日期：2013-07-30 00:00:00

abstract：:Shared random effects models have been increasingly common in the joint analyses of repeated measures (e.g. CD4 counts, hemoglobin levels) and a correlated failure time such as death. In this paper we study several shared random effects models in the multi-level repeated measures data setting with dependent failure ti...

journal_title：Statistics in medicine

authors： Liu L,Ma JZ,O'Quigley J

更新日期：2008-11-29 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：:Statistical methods are available for performing a meta-analysis when the response variable of interest is the same in each study. Problems arise when studies exploring a common therapeutic question use different patient response types. This article presents statistical methods for combining studies which involve diff...

journal_title：Statistics in medicine

authors： Whitehead A,Jones NM

更新日期：1994-12-15 00:00:00

abstract：:Geocoding a study population as completely as possible is an important data assimilation component of many spatial epidemiologic studies. Unfortunately, complete geocoding is rare in practice. The failure of a substantial proportion of study subjects' addresses to geocode has consequences for spatial analyses, some of...

journal_title：Statistics in medicine

authors： Zimmerman DL,Fang X,Mazumdar S

更新日期：2008-09-20 00:00:00

abstract：:Cost data that arise in the evaluation of health care technologies usually exhibit highly skew, heavy-tailed and, possibly, multi-modal distributions. Distribution-free methods for analysing these data, such as the bootstrap, or those based on the asymptotic normality of sample means, may often lead to inefficient or ...

journal_title：Statistics in medicine

authors： Conigliani C,Tancredi A

更新日期：2005-10-30 00:00:00

abstract：:We obtained maximum likelihood estimates (MLEs) of the proportion cured pi c and mean log survival time mu t for a sample of 4355 patients with intraocular melanoma whose survival times subsequent to treatment were assumed to follow a log-normal distribution. Following stratification by tumour size, MLEs of pi c and m...

journal_title：Statistics in medicine

authors： Gamel JW,McLean IW,Rosenberg SH

更新日期：1990-08-01 00:00:00

abstract：:In order for national statistical offices to maintain the trust of the public to collect data and publish statistics of importance to society and decision-making, it is imperative that respondents (persons or establishments) be guaranteed privacy and confidentiality in return for providing requested confidential data....

journal_title：Statistics in medicine

authors： Gonzalez JF Jr,Cox LH

更新日期：2005-02-28 00:00:00

abstract：:In any field in which decisions are subject to measurements, interchangeability between the methods used to obtain these measurements is essential. To consider methods as interchangeable, a certain degree of agreement is needed between the measurements they provide. The concordance correlation coefficient is an index ...

journal_title：Statistics in medicine

authors： Carrasco JL,Jover L

更新日期：2005-12-30 00:00:00