Inference without randomization or ignorability: A stability-controlled quasi-experiment on the prevention of tuberculosis.

abstract：:The time-dependent change of HIV particle load, i.e. HIV dynamics, is likely to be controlled by a multitude of quantitative trait loci (QTL) that interact with each other as well as with various developmental and environmental factors in a coordinated manner. In this article, we have derived a new statistical model f...

journal_title：Statistics in medicine

authors： Wu S,Yang J,Wu R

更新日期：2006-11-30 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：:In Part I we presented a covariance structure model for analysing measurement error in the assessment of nitrogen intake. In this paper we include data on urine nitrogen excretion which allows a critical assessment of the model proposed. Inclusion of urine nitrogen data produces more pessimistic estimates of the quali...

journal_title：Statistics in medicine

authors： Plummer M,Clayton D

更新日期：1993-05-30 00:00:00

abstract：:In analysis of longitudinal data, the variance matrix of the parameter estimates is usually estimated by the 'sandwich' method, in which the variance for each subject is estimated by its residual products. We propose smooth bootstrap methods by perturbing the estimating functions to obtain 'bootstrapped' realizations ...

journal_title：Statistics in medicine

authors： Li Y,Wang YG

更新日期：2008-03-30 00:00:00

abstract：:Recently, there has been much work on early phase cancer designs that incorporate both toxicity and efficacy data, called phase I-II designs because they combine elements of both phases. However, they do not explicitly address the phase II hypothesis test of H0 : p ≤ p0 , where p is the probability of efficacy at the ...

journal_title：Statistics in medicine

authors： Bartroff J,Lai TL,Narasimhan B

更新日期：2014-07-20 00:00:00

abstract：:The 'at least as good as' criterion, introduced by Laster and Johnson for a continuous response variate, is developed here for applications with dichotomous data. This approach is adaptive in nature, as the margin of non-inferiority is not taken as a fixed difference; it varies as a function of the positive control re...

journal_title：Statistics in medicine

authors： Laster LL,Johnson MF,Kotler ML

更新日期：2006-04-15 00:00:00

abstract：:We have formulated the problem of determining whether there has been an upturn in HIV-1 seroconversion incidence over the first five years of follow-up in the Multicenter AIDS Cohort Study (MACS) as that of locating the minimum of a quadratic regression or examination of two-knot piecewise spline models. Under a quadr...

journal_title：Statistics in medicine

authors： Zhou SY,Kingsley LA,Taylor JM,Chmiel JS,He DY,Hoover DR

更新日期：1993-01-30 00:00:00

abstract：:This paper introduces a new spatial scan statistic designed to adjust cluster detection for longitudinal confounding factors indexed in space. The functional-model-adjusted statistic was developed using generalized functional linear models in which longitudinal confounding factors were considered to be functional cova...

journal_title：Statistics in medicine

authors： Ahmed MS,Genin M

更新日期：2020-04-15 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：:Ordinal data appear in a wide variety of scientific fields. These data are often analyzed using ordinal logistic regression models that assume proportional odds. When this assumption is not met, it may be possible to capture the lack of proportionality using a constrained structural relationship between the odds and t...

journal_title：Statistics in medicine

authors： Capuano AW,Dawson JD

更新日期：2013-06-15 00:00:00

abstract：:In the presence of confounding, the consistency assumption required for identification of causal effects may be violated due to misclassification of the outcome variable. We introduce an inverse probability weighted approach to rebalance covariates across treatment groups while mitigating the influence of differential...

journal_title：Statistics in medicine

authors： Gravel CA,Platt RW

更新日期：2018-02-10 00:00:00

abstract：:An observed confidence distribution is proposed as a measure of strength of evidence for practically equivalent efficacies of two treatments. The concept is independent of prior opinions about relevant sizes of a difference in efficacy. It also avoids retrospective power calculations for trials with missed recruitment...

journal_title：Statistics in medicine

authors： Mau J

更新日期：1988-12-01 00:00:00

abstract：:Generalized linear models are often assumed to fit propensity scores, which are used to compute inverse probability weighted (IPW) estimators. To derive the asymptotic properties of IPW estimators, the propensity score is supposed to be bounded away from zero. This condition is known in the literature as strict positi...

journal_title：Statistics in medicine

authors： Molina J,Sued M,Valdora M

更新日期：2018-10-30 00:00:00

abstract：:Novel therapies are challenging the standards of drug development. Agents with specific biologic targets, unknown dose-efficacy curves, and limited toxicity mandate novel designs to identify biologically optimal doses. We review two model-based designs that utilize either a proportional odds model or a continuation ra...

journal_title：Statistics in medicine

authors： Mandrekar SJ,Qin R,Sargent DJ

更新日期：2010-05-10 00:00:00

abstract：:The mutation and natural selection phenomenon can and often does cause the failure of antimicrobial, herbicidal, pesticide and cancer treatments selection pressures. This phenomenon operates in a mathematically predictable behavior, which when understood leads to approaches to reduce and prevent the failure of the use...

journal_title：Statistics in medicine

authors： Kleinman A

更新日期：2014-12-20 00:00:00

abstract：:Rao proposed and compared several approaches for predicting future observations in a growth curve model. The assessment of associated prediction efficiency for different prediction methods were evaluated by Cross-Validation Assessment Error (CVAE). He used three data sets, each with a limited number of subjects (13-27...

journal_title：Statistics in medicine

authors： Tian JJ,Shukla R,Buncher CR

更新日期：1994-11-15 00:00:00

abstract：:Interim analyses are conducted to allow for early termination of the trial, for ethical as well as economical reasons. Here we consider interim analyses in repeated measurements studies where the measurements are binary. Two methods for analysing this kind of data are compared according to their operating characterist...

journal_title：Statistics in medicine

authors： Spiessens B,Lesaffre E,Verbeke G

更新日期：2003-02-28 00:00:00

abstract：:A decision-theoretic framework is proposed for designing sequential dose-finding trials with multiple outcomes. The optimal strategy is solvable theoretically via backward induction. However, for dose-finding studies involving k doses, the computational complexity is the same as the bandit problem with k-dependent arm...

journal_title：Statistics in medicine

authors： Fan SK,Wang YG

更新日期：2006-05-30 00:00:00

abstract：:The case-control study is a simple and an useful method to characterize the effect of a gene, the effect of an exposure, as well as the interaction between the two. The control-free case-only study is yet an even simpler design, if interest is centered on gene-environment interaction only. It requires the sometimes pl...

journal_title：Statistics in medicine

authors： Lee WC,Wang LY,Cheng KF

更新日期：2010-10-30 00:00:00

abstract：:The two-period cross-over design with two sequences of drug administration is a standard experimental design when bioequivalence of one test formulation is to be assessed in comparison with a reference formulation. Previously, an approach based on Fieller's confidence interval has been presented for the assessment of ...

journal_title：Statistics in medicine

authors： Vuorinen J

更新日期：1997-10-15 00:00:00

abstract：:The identification of new adverse drug reactions is often tricky. For a given case, the relationship between drug exposure and symptom occurrence is usually questionable. It could be investigated statistically from a series of drug-event association cases with an independence test between the two variables. Analysing ...

journal_title：Statistics in medicine

authors： Tubert P,Begaud B

更新日期：1991-06-01 00:00:00

abstract：:Researchers in clinical science and bioinformatics frequently aim to learn which of a set of candidate biomarkers is important in determining a given outcome, and to rank the contributions of the candidates accordingly. This article introduces a new approach to research questions of this type, based on targeted maximu...

journal_title：Statistics in medicine

authors： Bembom O,Petersen ML,Rhee SY,Fessel WJ,Sinisi SE,Shafer RW,van der Laan MJ

更新日期：2009-01-15 00:00:00

abstract：:In medical research, risk difference (RD) and number needed to treat (NNT) measures for survival times have been mainly proposed without consideration of covariates. In this paper, we develop adjusted RD and NNT measures for use in observational studies with survival time outcomes within the framework of the Cox propo...

journal_title：Statistics in medicine

authors： Laubender RP,Bender R

更新日期：2010-03-30 00:00:00

abstract：:Assessment of quality of life is becoming standard in clinical trials. A popular method for measuring quality of life is with instruments which utilize multiple-item subscales, in which each item is scored on a Likert scale. Most statistical methods for the analysis of quality of life data in clinical trials do not ex...

journal_title：Statistics in medicine

authors： Douglas JA

更新日期：1999-11-15 00:00:00

abstract：:This paper models monthly AIDS diagnosis counts in terms of smooth secular trend, calendar month effects, and the number of workdays per month. A parameterization of month effects allows separation of true seasonal effects from a linear trend over the calendar year and an arbitrary June effect. There is strong evidenc...

journal_title：Statistics in medicine

authors： Bacchetti P

更新日期：1994-10-15 00:00:00

abstract：:The introduction of potent antiretroviral therapies for treatment of HIV infection typically results in a dramatic reduction in plasma HIV RNA concentration, often to levels undetectable by current measurement practices. However, although a high proportion of patients achieve 'undetectability', many then experience a ...

journal_title：Statistics in medicine

authors： McKinnon EJ,James IR,John M,Mallal SA

更新日期：2003-02-15 00:00:00

abstract：:Inference for randomized clinical trials is generally based on the assumption that outcomes are independently and identically distributed under the null hypothesis. In some trials, particularly in infectious disease, outcomes may be correlated. This may be known in advance (e.g. allowing randomization of family member...

journal_title：Statistics in medicine

authors： Proschan M,Follmann D

更新日期：2008-03-15 00:00:00

abstract：:The mixed effect models for repeated measures (MMRM) analysis is sometimes used as a primary analysis in longitudinal randomized clinical trials. The SE for the treatment effect in the MMRM analysis is usually estimated by assuming the orthogonality of the fixed effect and variance-covariance parameters, which is the ...

journal_title：Statistics in medicine

authors： Maruo K,Ishii R,Yamaguchi Y,Doi M,Gosho M

更新日期：2020-04-30 00:00:00

abstract：:There is considerable public concern about health disparities among different cultural/racial/ethnic groups. Important process measures that might reflect inequities are treated prevalence and the service utilization rate in a defined period of time. We have previously described a method for estimating N, the distinct...

journal_title：Statistics in medicine

authors： Laska EM,Meisner M,Wanderling J,Siegel C

更新日期：2010-07-20 00:00:00

abstract：:We extend the method proposed in a recent work by the Authors for trial-level general surrogate evaluation to allow combinations of biomarkers and provide a procedure for finding the "best" combination of biomarkers based on the absolute prediction error summary of surrogate quality. We use a nonparametric Bayesian mo...

journal_title：Statistics in medicine

authors： Gabriel EE,Sachs MC,Daniels MJ,Halloran ME

更新日期：2019-03-30 00:00:00