Internal pilot studies I: type I error rate of the naive t-test.

abstract：:Austin Bradford Hill was once a friend to The Lancet, but, as occasionally happens, friends fall out. The great legacy of his association with the journal, however, was Principles of Medical Statistics. As each edition was succeeded by another--the first in 1937, the last in 1991--he seemed to shift his view about the...

journal_title：Statistics in medicine

authors： Horton R

更新日期：2000-12-15 00:00:00

abstract：:Having a surrogate for a definitive endpoint in a clinical trial can sometimes be useful when it is impractical, invasive or very time consuming to obtain the definitive endpoint. This paper discusses methods for assessing whether the surrogate-endpoint results of a trial can be used in place of definitive-endpoint re...

journal_title：Statistics in medicine

authors： Korn EL,Albert PS,McShane LM

更新日期：2005-01-30 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：:Confidence intervals for a standardized effect are derived after stabilizing the variance of the Welch t-statistic. Simulation studies demonstrate the viability of the resulting intervals for a wide range of parameter values and sample sizes as small as five. The methodology is extended to the combination of results f...

journal_title：Statistics in medicine

authors： Kulinskaya E,Staudte RG

更新日期：2007-06-30 00:00:00

abstract：:It is not uncommon for a continuous outcome variable Y to be dichotomized and analysed using logistic regression. Moser and Coombs (Statist. Med. 2004; 23:1843-1860) provide a method for converting the output from a standard linear regression analysis using the original continuous outcome Y to give much more efficient...

journal_title：Statistics in medicine

authors： Jiang Y,Scott A,Wild CJ

更新日期：2009-01-30 00:00:00

abstract：:With reference to a real data on cataract surgery, we discuss the problem of zero-inflated circular-circular regression when both covariate and response are circular random variables and a large proportion of the responses are zeros. The regression model is proposed, and the estimation procedure for the parameters is ...

journal_title：Statistics in medicine

authors： Jha J,Biswas A

更新日期：2018-01-15 00:00:00

abstract：:The identification of changes in the recent trend is an important issue in the analysis of cancer mortality and incidence data. We apply a joinpoint regression model to describe such continuous changes and use the grid-search method to fit the regression function with unknown joinpoints assuming constant variance and ...

journal_title：Statistics in medicine

authors： Kim HJ,Fay MP,Feuer EJ,Midthune DN

更新日期：2000-02-15 00:00:00

abstract：:We consider the use of the assurance method in clinical trial planning. In the assurance method, which is an alternative to a power calculation, we calculate the probability of a clinical trial resulting in a successful outcome, via eliciting a prior probability distribution about the relevant treatment effect. This i...

journal_title：Statistics in medicine

authors： Ren S,Oakley JE

更新日期：2014-01-15 00:00:00

abstract：:The identification of counties burdened by exceptionally high rates of mortality is a fundamental step in the development of state-based intervention and prevention strategies. However, the estimation of rates from small geographic areas presents special problems, especially for rare events. This paper compares the us...

journal_title：Statistics in medicine

authors： Stevenson JM,Olson DR

更新日期：1993-02-01 00:00:00

abstract：:There is growing interest in how best to adapt and readapt treatments to individuals to maximize clinical benefit. In response, adaptive treatment strategies (ATS), which operationalize adaptive, sequential clinical decision making, have been developed. From a patient's perspective an ATS is a sequence of treatments, ...

journal_title：Statistics in medicine

authors： Almirall D,Compton SN,Gunlicks-Stoessel M,Duan N,Murphy SA

更新日期：2012-07-30 00:00:00

abstract：:Hypothesis testing, in which the null hypothesis specifies no difference between treatment groups, is an important tool in the assessment of new medical interventions. For randomized clinical trials, permutation tests that reflect the actual randomization are design-based analyses for such hypotheses. This means that ...

journal_title：Statistics in medicine

authors： Berger VW

更新日期：2000-05-30 00:00:00

abstract：:Clustered grouped survival data arise naturally in clinical medicine and biological research. For example, in a randomized clinical trial, the variable of interest is the time to occurrence of a certain event with or without a new treatment and the data are collected from possibly correlated subjects from independent ...

journal_title：Statistics in medicine

authors： Lam KF,Ip D

更新日期：2003-06-30 00:00:00

abstract：:The matched case-control designs are commonly used to control for potential confounding factors in genetic epidemiology studies especially epigenetic studies with DNA methylation. Compared with unmatched case-control studies with high-dimensional genomic or epigenetic data, there have been few variable selection metho...

journal_title：Statistics in medicine

authors： Sun H,Wang S

更新日期：2013-05-30 00:00:00

abstract：:We study prevalence-dependent diagnostic accuracy measures, specifically, positive and negative predictive values. These measures permit an assessment of the clinical utility of diagnostic tests across populations with different disease prevalences. In many cases, prevalence may not be known with certainty and the eva...

journal_title：Statistics in medicine

authors： Li J,Fine JP,Safdar N

更新日期：2007-07-30 00:00:00

abstract：:Screening and diagnostic tests are important in disease prevention or control. The predictive values of positive and negative (PPV and NPV) test results are two of four operational characteristics of a screening test. We review an existing method based on the generalized estimating equation (GEE) methodology for compa...

journal_title：Statistics in medicine

authors： Wang W,Davis CS,Soong SJ

更新日期：2006-07-15 00:00:00

abstract：:In multiple-record systems estimation it is usually assumed that all registration relate to the same population. In this paper, we develop a method which can be used when the registrations relate to different populations, in the sense that they cover, for example, different time periods or regions. We show that under ...

journal_title：Statistics in medicine

authors： Zwane EN,van der Pal-de Bruin K,van der Heijden PG

更新日期：2004-07-30 00:00:00

abstract：:Outcomes research often requires estimating the impact of a binary treatment on a binary outcome in a non-randomized setting, such as the effect of taking a drug on mortality. The data often come from self-selected samples, leading to a spurious correlation between the treatment and outcome when standard binary depend...

journal_title：Statistics in medicine

authors： Bhattacharya J,Goldman D,McCaffrey D

更新日期：2006-02-15 00:00:00

abstract：:Statistical inference based on correlated count measurements are frequently performed in biomedical studies. Most of existing sample size calculation methods for count outcomes are developed under the Poisson model. Deviation from the Poisson assumption (equality of mean and variance) has been widely documented in pra...

journal_title：Statistics in medicine

authors： Li D,Zhang S,Cao J

更新日期：2019-12-10 00:00:00

abstract：:Multistate models are increasingly being used to model complex disease profiles. By modelling transitions between disease states, accounting for competing events at each transition, we can gain a much richer understanding of patient trajectories and how risk factors impact over the entire disease pathway. In this arti...

journal_title：Statistics in medicine

authors： Crowther MJ,Lambert PC

更新日期：2017-12-20 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：:Box-Cox transformation is investigated for regression models for left-censored data. Examples are provided using coronary calcification data from the Multi-Ethnic Study of Atherosclerosis and pharmacokinetic data of a nicotine nasal spray. ...

journal_title：Statistics in medicine

authors： Han C,Kronmal R

更新日期：2004-12-15 00:00:00

abstract：:A mixed effect model is proposed to jointly analyze multivariate longitudinal data with continuous, proportion, count, and binary responses. The association of the variables is modeled through the correlation of random effects. We use a quasi-likelihood type approximation for nonlinear variables and transform the prop...

journal_title：Statistics in medicine

authors： Li H,Zhang Y,Carroll RJ,Keadle SK,Sampson JN,Matthews CE

更新日期：2017-11-10 00:00:00

abstract：:Mediation analysis is a standard approach to understanding how and why an intervention works in social and medical sciences. However, the presence of missing data, especially missing not at random data, poses a great challenge for the applicability of this approach in practice. Current methods for handling such missin...

journal_title：Statistics in medicine

authors： Li W,Zhou XH

更新日期：2017-11-10 00:00:00

abstract：:Important differences between explanatory and pragmatic studies were originally argued by Schwartz and Lellouch. Three important differences between the two types of study involve study control, study violators and inclusion criteria. It was originally argued that explanatory studies are highly controlled, and pragmat...

journal_title：Statistics in medicine

authors： McMahon AD

更新日期：2002-05-30 00:00:00

abstract：:Motivated by a study about prompt coronary angiography in myocardial infarction, we propose a method to estimate the causal effect of a treatment in two-arm experimental studies with possible noncompliance in both treatment and control arms. We base the method on a causal model for repeated binary outcomes (before and...

journal_title：Statistics in medicine

authors： Bartolucci F,Farcomeni A

更新日期：2013-11-10 00:00:00

abstract：:Binary matched-pairs data occur commonly in longitudinal studies, such as in cross-over experiments. Many analyses for comparing the matched probabilities of a particular outcome do not utilize pairs having the same outcome for each observation. An example is McNemar's test. Some methodologists find this to be counter...

journal_title：Statistics in medicine

authors： Agresti A,Min Y

更新日期：2004-01-15 00:00:00

abstract：:The problem of testing symmetry about zero has a long and rich history in the statistical literature. We introduce a new test that sequentially discards observations whose absolute value is below increasing thresholds defined by the data. McNemar's statistic is obtained at each threshold and the largest is used as the...

journal_title：Statistics in medicine

authors： Laska E,Meisner M,Wanderling J

更新日期：2012-11-20 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：: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：:Instrumental variable estimates of causal effects can be biased when using many instruments that are only weakly associated with the exposure. We describe several techniques to reduce this bias and estimate corrected standard errors. We present our findings using a simulation study and an empirical application. For th...

journal_title：Statistics in medicine

authors： Davies NM,von Hinke Kessler Scholder S,Farbmacher H,Burgess S,Windmeijer F,Smith GD

更新日期：2015-02-10 00:00:00