Validity of tests under covariate-adaptive biased coin randomization and generalized linear models.

abstract：:We develop locally D-optimal designs for nonlinear models when the variance of the response is a function of its mean. Using the two-parameter Michaelis-Menten model as an example, we show that the optimal design depends on both the type of heteroscedasticity and the magnitude of the variation. In addition, our result...

journal_title：Biometrics

authors： Dette H,Wong WK

更新日期：1999-09-01 00:00:00

abstract：:We consider the problem of testing for a difference in the probability of success from matched binary pairs. Starting with three standard inexact tests, the nuisance parameter is first estimated and then the residual dependence is eliminated by maximization, producing what I call an E+M P-value. The E+M P-value based ...

journal_title：Biometrics

authors： Lloyd CJ

更新日期：2008-09-01 00:00:00

abstract：:Stepped wedge designed trials are a type of cluster-randomized study in which the intervention is introduced to each cluster in a random order over time. This design is often used to assess the effect of a new intervention as it is rolled out across a series of clinics or communities. Based on a permutation argument, ...

journal_title：Biometrics

authors： Hughes JP,Heagerty PJ,Xia F,Ren Y

更新日期：2020-03-01 00:00:00

abstract：:Ranked set sampling (RSS) utilizes inexpensive auxiliary information about the ranking of the units in a sample to provide a more precise estimator of the population mean of the variable of interest Y, which is either difficult or expensive to measure. However, the ranking may not be perfect in most situations. In thi...

journal_title：Biometrics

authors： Yu PL,Lam K

更新日期：1997-09-01 00:00:00

abstract：:Gene-disease association studies based on case-control designs may often be used to identify candidate polymorphisms (markers) conferring disease risk. If a large number of markers are studied, genotyping all markers on all samples is inefficient in resource utilization. Here, we propose an alternative two-stage metho...

journal_title：Biometrics

authors： Satagopan JM,Venkatraman ES,Begg CB

更新日期：2004-09-01 00:00:00

abstract：:For patients with chronic myelogenous leukemia (CML), the effect of elevated blood levels of adenosine deaminase (ADA) is studied as a marker for transitions from stable disease to blast crisis and then to death. Data in the form of snapshots over time, with day, state of disease, and ADA level, are analyzed for 55 pa...

journal_title：Biometrics

authors： Klein JP,Klotz JH,Grever MR

更新日期：1984-12-01 00:00:00

abstract：:We propose a new estimation method for multivariate failure time data using the quadratic inference function (QIF) approach. The proposed method efficiently incorporates within-cluster correlations. Therefore, it is more efficient than those that ignore within-cluster correlation. Furthermore, the proposed method is e...

journal_title：Biometrics

authors： Xue L,Wang L,Qu A

更新日期：2010-06-01 00:00:00

abstract：:In this article, we demonstrate a statistical method for fitting the parameters of a sophisticated network and epidemic model to disease data. The pattern of contacts between hosts is described by a class of dyadic independence exponential-family random graph models (ERGMs), whereas the transmission process that runs ...

journal_title：Biometrics

authors： Groendyke C,Welch D,Hunter DR

更新日期：2012-09-01 00:00:00

abstract：:In this paper, a Markov process is developed as a mathematical model to study the general problem of quality control monitoring. This approach was previously used by Arnold (1970) in development of sampling plans to study the water quality monitoring of streams. Arnold considered the expected sample size required for ...

journal_title：Biometrics

authors： Smeach SC,Jernigan RW

更新日期：1977-03-01 00:00:00

abstract：:A multiple toxicity model for the quantal response of organisms is constructed based on an existing bivariate theory. The main assumption is that the tolerances follow a multivariate normal distribution function. However, any monotone tolerance distribution can be applied by mapping the integration region in the n-dim...

journal_title：Biometrics

authors： Christensen ER,Chen CY

更新日期：1985-09-01 00:00:00

abstract：:This article presents a new approach for exploring the distribution of interindividual random effects in nonlinear mixed effect models. The approach introduces a spline function, which transforms an assumed normally distributed interindividual random effect to an arbitrary distribution approximating that of the data. ...

journal_title：Biometrics

authors： Fattinger KE,Sheiner LB,Verotta D

更新日期：1995-12-01 00:00:00

abstract：:The paper here presented was motivated by a case study involving high-dimensional and high-frequency tidal volume traces measured during induced panic attacks. The focus was to develop a procedure to determine the significance of whether a mean curve dominates another one. The key idea of the suggested method relies o...

journal_title：Biometrics

authors： Lee SH,Lim J,Vannucci M,Petkova E,Preter M,Klein DF

更新日期：2008-09-01 00:00:00

abstract：:Estimates of waterfowl demographic parameters often come from resighting studies where birds fit with individually identifiable neck collars are resighted at a distance. Concerns have been raised about the effects of collar loss on parameter estimates, and the reliability of extrapolating from collared individuals to ...

journal_title：Biometrics

authors： Conn PB,Kendall WL,Samuel MD

更新日期：2004-12-01 00:00:00

abstract：:Traditional paradigms for clinical translation are challenged in settings where multiple contemporaneous therapeutic strategies have been identified as potentially beneficial. Platform trials have emerged as an approach for sequentially comparing multiple trials using a single protocol. The Ebola virus disease outbrea...

journal_title：Biometrics

authors： Kaizer AM,Hobbs BP,Koopmeiners JS

更新日期：2018-09-01 00:00:00

abstract：:In a study designed to assess the relationship between a dichotomous exposure and the eventual occurrence of a dichotomous outcome, frequency matching has been proposed as a way to balance the exposure cohorts with respect to the sampling distribution of potential confounding factors. This paper discusses the pooled e...

journal_title：Biometrics

authors： Weinberg CR

更新日期：1985-03-01 00:00:00

abstract：:In Western countries where food supply is satisfactory, consumers organize their diets around a large combination of foods. It is the purpose of this article to examine how recent nonnegative matrix factorization (NMF) techniques can be applied to food consumption data to understand these combinations. Such data are n...

journal_title：Biometrics

authors： Zetlaoui M,Feinberg M,Verger P,Clémençon S

更新日期：2011-12-01 00:00:00

abstract：:An important objective in biomedical and environmental risk assessment is estimation of minimum exposure levels that induce a pre-specified adverse response in a target population. The exposure points in such settings are typically referred to as benchmark doses (BMDs). Parametric Bayesian estimation for finding BMDs ...

journal_title：Biometrics

authors： Fang Q,Piegorsch WW,Simmons SJ,Li X,Chen C,Wang Y

更新日期：2015-12-01 00:00:00

abstract：:In the evaluation of diagnostic accuracy of tests, a gold standard on the disease status is required. However, in many complex diseases, it is impossible or unethical to obtain such a gold standard. If an imperfect standard is used, the estimated accuracy of the tests would be biased. This type of bias is called imper...

journal_title：Biometrics

authors： Zhou XH,Castelluccio P,Zhou C

更新日期：2005-06-01 00:00:00

abstract：:In the analysis of longitudinal or panel data, neglecting the serial correlations among the repeated measurements within subjects may lead to inefficient inference. In particular, when the number of repeated measurements is large, it may be desirable to model the serial correlations more generally. An appealing approa...

journal_title：Biometrics

authors： Qiu J,Wu L

更新日期：2015-09-01 00:00:00

abstract：:In principle, G-estimation is an attractive approach for dealing with confounding by variables affected by treatment. It has rarely been applied for estimation of the effects of treatment on failure-time outcomes. Part of this is due to artificial censoring, an analytic device which considers some subjects who actuall...

journal_title：Biometrics

authors： Joffe MM,Yang WP,Feldman H

更新日期：2012-03-01 00:00:00

abstract：:Estimation of treatment effects in randomized studies is often hampered by possible selection bias induced by conditioning on or adjusting for a variable measured post-randomization. One approach to obviate such selection bias is to consider inference about treatment effects within principal strata, that is, principal...

journal_title：Biometrics

authors： Long DM,Hudgens MG

更新日期：2013-12-01 00:00:00

abstract：:The Colton model for the choice between two medical treatments is studied, with the additional assumption that there is a time lag between the administration of the treatments and the availability of the responses. Two simple procedures are suggested for dealing with patients who arrive during the waiting period, caus...

journal_title：Biometrics

authors： Langenberg P,Srinivasan R

更新日期：1981-03-01 00:00:00

abstract：:One common method for estimating total catch is to multiply an estimate for CPUE, the catch per unit effort, by an estimate of total effort obtained from an independent second survey. In general, estimating total effort requires that sample times are chosen at random over the full fishing period; however, in practice,...

journal_title：Biometrics

authors： Dauk PC,Schwarz CJ

更新日期：2001-06-01 00:00:00

abstract：:Serial dilution assays are widely employed for estimating substance concentrations and minimum inhibitory concentrations. The Poisson-Bernoulli model for such assays is appropriate for count data but not for continuous measurements that are encountered in applications involving substance concentrations. This paper pre...

journal_title：Biometrics

authors： Lee ML,Whitmore GA

更新日期：1999-12-01 00:00:00

abstract：:Large amounts of longitudinal health records are now available for dynamic monitoring of the underlying processes governing the observations. However, the health status progression across time is not typically observed directly: records are observed only when a subject interacts with the system, yielding irregular and...

journal_title：Biometrics

authors： Luo Y,Stephens DA,Verma A,Buckeridge DL

更新日期：2020-03-11 00:00:00

abstract：:In longitudinal observational studies, repeated measures are often taken at informative observation times. Also, there may exist a dependent terminal event such as death that stops the follow-up. For example, patients in poorer health are more likely to seek medical treatment and their medical cost for each visit tend...

journal_title：Biometrics

authors： Liu L,Huang X,O'Quigley J

更新日期：2008-09-01 00:00:00

abstract：:A method is proposed for calculating the probabilities of assignment of a patient to treatments; it involves minimizing a quadratic criterion subject to a balance constraint. The optimal probabilities are very easy to compute. Numerical illustration is given and comparisons are drawn with the entropy-based methods of ...

journal_title：Biometrics

authors： Titterington DM

更新日期：1983-12-01 00:00:00

abstract：:Many problems that appear in biomedical decision-making, such as diagnosing disease and predicting response to treatment, can be expressed as binary classification problems. The support vector machine (SVM) is a popular classification technique that is robust to model misspecification and effectively handles high-dime...

journal_title：Biometrics

authors： Luckett DJ,Laber EB,El-Kamary SS,Fan C,Jhaveri R,Perou CM,Shebl FM,Kosorok MR

更新日期：2020-08-31 00:00:00

abstract：:Detecting changes in longitudinal data is important in medical research. However, the existence of measurement outliers can cause an unexpected increase in the false alarm rate in claiming changes. To reduce the outliers, a new method has been developed. In this scheme, two measures are initially taken and, if they ar...

journal_title：Biometrics

authors： Namgung YY,Yang MC

更新日期：1994-03-01 00:00:00

abstract：:Recent developments in the Cormack-Jolly-Seber (CJS) model for analyzing capture-recapture data have focused on allowing the capture and survival rates to vary between individuals. Several methods have been developed in which capture and survival are functions of auxiliary variables that may be discrete, constant over...

journal_title：Biometrics

authors： Bonner SJ,Schwarz CJ

更新日期：2006-03-01 00:00:00