Sample sizes for constructing confidence intervals and testing hypotheses.

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：:Observational studies provide a rich source of information for assessing effectiveness of treatment interventions in many situations where it is not ethical or practical to perform randomized controlled trials. However, such studies are prone to bias from hidden (unmeasured) confounding. A promising approach to identi...

journal_title：Statistics in medicine

authors： Lin NX,Henley WE

更新日期：2016-12-10 00:00:00

abstract：:Within the rich literature on generalized linear models, substantial efforts have been devoted to models for categorical responses that are either completely ordered or completely unordered. Few studies have focused on the analysis of partially ordered outcomes, which arise in practically every area of study, includin...

journal_title：Statistics in medicine

authors： Zhang Q,Ip EH

更新日期：2012-01-13 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：:This paper investigates the design and analysis of dose-finding trials with two agents. The set of doses for each agent is fixed in advance. The goal of the trial is to find the set of dose combinations with probability of toxicity closest to a pre-specified value. For each of the two agents we assume that the probabi...

journal_title：Statistics in medicine

authors： Ivanova A,Wang K

更新日期：2004-06-30 00:00:00

abstract：:In many chronic diseases, therapy aims to prevent or reduce the frequency of episodes of a disease manifestation, for example cardiac ischaemic episodes or epileptic seizures. Entry criteria for clinical trials typically include a minimum number of episodes within a baseline period, and regression to the mean should b...

journal_title：Statistics in medicine

authors： McMahon RP,Proschan M,Geller NL,Stone PH,Sopko G

更新日期：1994-04-30 00:00:00

abstract：:In the analysis of composite endpoints in a clinical trial, time to first event analysis techniques such as the logrank test and Cox proportional hazard test do not take into account the multiplicity, importance, and the severity of events in the composite endpoint. Several generalized pairwise comparison analysis met...

journal_title：Statistics in medicine

authors： Verbeeck J,Spitzer E,de Vries T,van Es GA,Anderson WN,Van Mieghem NM,Leon MB,Molenberghs G,Tijssen J

更新日期：2019-12-30 00:00:00

abstract：:In applications such as medical statistics and genetics, we encounter situations where a large number of highly correlated predictors explain a response. For example, the response may be a disease indicator and the predictors may be treatment indicators or single nucleotide polymorphisms (SNPs). Constructing a good pr...

journal_title：Statistics in medicine

authors： Sperrin M,Jaki T

更新日期：2010-10-30 00:00:00

abstract：:We compared eight nominal 95 per cent confidence intervals for the ratio of two Poisson parameters, both assumed small, on their true coverage (the probability that the interval includes the ratio of Poisson parameters) and median width. The commonly used log-linear interval, justified by asymptotic considerations, pr...

journal_title：Statistics in medicine

authors： Barker L,Cadwell BL

更新日期：2008-09-10 00:00:00

abstract：:Epidemiologic and clinical studies routinely collect longitudinal measures of multiple outcomes, including biomarker measures, cognitive functions, and clinical symptoms. These longitudinal outcomes can be used to establish the temporal order of relevant biological processes and their association with the onset of cli...

journal_title：Statistics in medicine

authors： Yang L,Gao S

更新日期：2013-03-15 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：:Correlation analysis is widely used in biomedical and psychosocial research for assessing rater reliability, precision of diagnosis and accuracy of proxy outcomes. The popularity of longitudinal study designs has propelled the proliferation in recent years of new methods for longitudinal and other multi-level clustere...

journal_title：Statistics in medicine

authors： Tu XM,Feng C,Kowalski J,Tang W,Wang H,Wan C,Ma Y

更新日期：2007-09-30 00:00:00

abstract：:We propose a goodness-of-fit test statistic for linear regression with heterogeneous variance, which is asymptotically chi-square if the given model is correct. The test statistic is computed as a quadratic form of observed minus predicted responses. We apply the method to a linear regression for an ordinal categorica...

journal_title：Statistics in medicine

authors： Lipsitz SR,Buoncristiani JF

更新日期：1994-01-30 00:00:00

abstract：:In this paper, we define a modified version τ(b) of Kendall's tau to measure the association in a pair (X,Y) of random variables subject to fixed left censoring due to known lower detection limits. We provide a nonparametric estimator of τ(b) and investigate its asymptotic properties. We then assume an Archimedean cop...

journal_title：Statistics in medicine

authors： Romdhani H,Lakhal-Chaieb L

更新日期：2011-11-20 00:00:00

abstract：:With the increasing availability of detailed clinical information, there is optimism that treatment choices can be selectively directed to those individuals most likely to benefit. While standard clinical trials can establish whether a treatment appears to be effective on average, subsequent work is needed to determin...

journal_title：Statistics in medicine

authors： Sitlani CM,Heagerty PJ

更新日期：2014-07-30 00:00:00

abstract：:Data monitoring committees (DMCs) have become an increasingly common component of randomized clinical trials in recent years. As experience has accumulated, and more individuals and organizations have become involved in such activities, a variety of approaches to the operation of such committees has inevitably arisen....

journal_title：Statistics in medicine

authors： Ellenberg SS

更新日期：2001-09-15 00:00:00

abstract：:Instrumental variable is an essential tool for addressing unmeasured confounding in observational studies. Two-stage predictor substitution (2SPS) estimator and two-stage residual inclusion (2SRI) are two commonly used approaches in applying instrumental variables. Recently, 2SPS was studied under the additive hazards...

journal_title：Statistics in medicine

authors： Ying A,Xu R,Murphy J

更新日期：2019-05-10 00:00:00

abstract：:A new method is proposed for the surveillance of Down's syndrome among newborn. Despite the strong dependence of overall risk of Down's syndrome on maternal age, it has been suggested that an environmentally induced increase in risk may be additive over all maternal ages. The surveillance method introduced here is spe...

journal_title：Statistics in medicine

authors： Lie RT,Heuch I,Irgens LM

更新日期：1993-01-15 00:00:00

abstract：:Summarizing the information of many studies using a meta-analysis becomes more and more important, also in the field of diagnostic studies. The special challenge in meta-analysis of diagnostic accuracy studies is that in general sensitivity and specificity are co-primary endpoints. Across the studies both endpoints ar...

journal_title：Statistics in medicine

authors： Zapf A,Hoyer A,Kramer K,Kuss O

更新日期：2015-12-20 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：:Epidermal nerve fibre (ENF) density and morphology are used to study small fibre involvement in diabetic, HIV, chemotherapy induced and other neuropathies. ENF density and summed length of ENFs per epidermal surface area are reduced, and ENFs may appear more clustered within the epidermis in subjects with small fibre ...

journal_title：Statistics in medicine

authors： Andersson C,Guttorp P,Särkkä A

更新日期：2016-10-30 00:00:00

abstract：:The principles and historical development of clinical trials are outlined briefly. Some issues that extend the basic philosophy first put forward by Sir Austin Bradford Hill 40 years ago and that will need consideration in the future application of clinical trials are discussed. ...

journal_title：Statistics in medicine

authors： Holland WW,Breeze E,Swan AV

更新日期：1982-10-01 00:00:00

abstract：:Meta-analysis has generally been accepted as a fundamental tool for combining effect estimates from several studies. For binary studies with rare events, the Peto odds ratio (POR) method has become the relative effect estimator of choice. However, the POR leads to biased estimates for the OR when treatment effects are...

journal_title：Statistics in medicine

authors： Brockhaus AC,Bender R,Skipka G

更新日期：2014-12-10 00:00:00

abstract：:For robust detection performance, traditional control chart monitoring for biosurveillance is based on input data free of trends, day-of-week effects, and other systematic behaviour. Time series forecasting methods may be used to remove this behaviour by subtracting forecasts from observations to form residuals for al...

journal_title：Statistics in medicine

authors： Burkom HS,Murphy SP,Shmueli G

更新日期：2007-09-30 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：:The generalized estimating equations (GEE) approach is commonly used to model incomplete longitudinal binary data. When drop-outs are missing at random through dependence on observed responses (MAR), GEE may give biased parameter estimates in the model for the marginal means. A weighted estimating equations approach g...

journal_title：Statistics in medicine

authors： Preisser JS,Lohman KK,Rathouz PJ

更新日期：2002-10-30 00:00:00

abstract：:Parameters for latent transition analysis (LTA) are easily estimated by maximum likelihood (ML) or Bayesian method via Markov chain Monte Carlo (MCMC). However, unusual features in the likelihood can cause difficulties in ML and Bayesian inference and estimation, especially with small samples. In this study we explore...

journal_title：Statistics in medicine

authors： Chung H,Lanza ST,Loken E

更新日期：2008-05-20 00:00:00

abstract：:In a phase I clinical trial in cancer patients, the drug involved had one known main adverse effect, which also occurs spontaneously in cancer patients with a fairly high frequency. Experiments in rats have shown marked effects of the drug on tumour growth in high doses, but also dose-dependent toxicity. Consequently,...

journal_title：Statistics in medicine

authors： Møller S

更新日期：1995-05-15 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：:Longitudinal studies are often concerned with estimating the recurrence rate of a non-fatal event. In many cases, only the total number of events occurring during successive time intervals is known. We compared a mixed Poisson-gamma regression method proposed by Thall and a quasi-likelihood method proposed by Zeger an...

journal_title：Statistics in medicine

authors： Stukel TA

更新日期：1993-07-30 00:00:00