Comparison of non parallel immunoassay curves resulting from mixtures of competing antigens.

abstract：:Methods for dealing with tied event times in the Cox proportional hazards model are well developed. Also, the partial likelihood provides a natural way to handle covariates that change over time. However, ties between event times and the times that discrete time-varying covariates change have not been systematically s...

journal_title：Statistics in medicine

authors： Xin X,Horrocks J,Darlington GA

更新日期：2013-06-30 00:00:00

abstract：:To benefit Alzheimer's disease research, a central data co-ordinating centre (CDCC) is planned that will systematically collect data from 27 Alzheimer's disease centres (ADCs) located nationwide. This CDCC will combine, analyse and disseminate epidemiologic, demographic, clinical and neuropathological data to research...

journal_title：Statistics in medicine

authors： Cronin-Stubbs D,DeKosky ST,Morris JC,Evans DA

更新日期：2000-06-15 00:00:00

abstract：:Rationalization of antibiotic therapy in the management of infectious diseases is helped by a knowledge of the patterns of sensitivity and resistance of bacteria to antibiotics and their possible changes both in time and from one hospital unit to another. In this paper we present the results regarding the sensitivitie...

journal_title：Statistics in medicine

authors： Bonetto C,Giannerini S,Giovagnoli A

更新日期：2006-10-30 00:00:00

abstract：:In the recent two decades, data mining methods for signal detection have been developed for drug safety surveillance, using large post-market safety data. Several of these methods assume that the number of reports for each drug-adverse event combination is a Poisson random variable with mean proportional to the unknow...

journal_title：Statistics in medicine

authors： Hu N,Huang L,Tiwari RC

更新日期：2015-08-30 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：: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：:I discuss alternatives to the one compartment model, delta Yt = alpha + beta exp(- gamma t). Instead of comparing the one and two compartment models, I derive statistics for testing mixtures of the parameters (beta, gamma) in the one compartment model. I apply the proposed methods to the problem of hydrogen clearance ...

journal_title：Statistics in medicine

authors： Zelterman D

更新日期：1989-08-01 00:00:00

abstract：:Interval-censored survival data often occur in medical studies, especially in clinical trials. In this case, many authors have considered estimation of a survival function. There is, however, relatively little discussion on estimating the variance of estimated survival functions. For right-censored data, a special cas...

journal_title：Statistics in medicine

authors： Sun J

更新日期：2001-04-30 00:00:00

abstract：:Studies involving longitudinal binary responses are widely applied in the health and biomedical sciences research and frequently analyzed by generalized estimating equations (GEE) method. This article proposes an alternative goodness-of-fit test based on the nonparametric smoothing approach for assessing the adequacy ...

journal_title：Statistics in medicine

authors： Lin KC,Chen YJ,Shyr Y

更新日期：2008-09-30 00:00:00

abstract：:We consider the design of both cohort and case-control studies in which an initial ('stage 1') sample of complete data on an error-free disease indicator (D), a correct ('gold standard') dichotomous exposure measurement (X) and an error-prone exposure measurement (Z) are available. We calculate the amount of additiona...

journal_title：Statistics in medicine

authors： Dahm PF,Gail MH,Rosenberg PS,Pee D

更新日期：1995-12-15 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：:Typical analyses of lifetime data treat the time to death or failure as the response variable and use a variety of modelling strategies such as proportional hazards or fully parametric, to investigate the relationship between the response and covariates. In certain circumstances it may be more natural to view the dist...

journal_title：Statistics in medicine

authors： Ghahramani M,Dean CB,Spinelli JJ

更新日期：2001-07-15 00:00:00

abstract：:In vaccine safety studies, subjects are considered at increased risk for adverse events for a period of time after vaccination known as risk window. To our knowledge, risk windows for vaccine safety studies have tended to be pre-defined and not to use information from the current study. Inaccurate specification of the...

journal_title：Statistics in medicine

authors： Xu S,Zhang L,Nelson JC,Zeng C,Mullooly J,McClure D,Glanz J

更新日期：2011-03-30 00:00:00

abstract：:Various R(2) statistics have been proposed for logistic regression to quantify the extent to which the binary response can be predicted by a given logistic regression model and covariates. We study the asymptotic properties of three popular variance-based R(2) statistics. We find that two variance-based R(2) statistic...

journal_title：Statistics in medicine

authors： Hu B,Palta M,Shao J

更新日期：2006-04-30 00:00:00

abstract：:In a variety of biomedical applications, particularly those involving screening for infectious diseases, testing individuals (e.g. blood/urine samples, etc.) in pools has become a standard method of data collection. This experimental design, known as group testing (or pooled testing), can provide a large reduction in ...

journal_title：Statistics in medicine

authors： Chen P,Tebbs JM,Bilder CR

更新日期：2009-10-15 00:00:00

abstract：:Spatial scan statistics are widely used for count data to detect geographical disease clusters of high or low incidence, mortality or prevalence and to evaluate their statistical significance. Some data are ordinal or continuous in nature, however, so that it is necessary to dichotomize the data to use a traditional s...

journal_title：Statistics in medicine

authors： Jung I,Kulldorff M,Klassen AC

更新日期：2007-03-30 00:00:00

abstract：:Proportional odds regression models for multinomial probabilities based on ordered categories have been generalized in two somewhat different directions. Models having scale as well as location parameters for adjustment of boundaries (on an unobservable, underlying continuum) between categories have been employed in t...

journal_title：Statistics in medicine

authors： Cox C

更新日期：1995-06-15 00:00:00

abstract：:A statistical analysis is presented of the intensities of admissions to psychiatric hospitals among women in Denmark who either gave birth to a child in the year 1975 or had an induced abortion in the same year. The models used are time-continuous Markov and semi-Markov processes, and the methods employed include non-...

journal_title：Statistics in medicine

authors： Andersen PK,Rasmussen NK

更新日期：1986-05-01 00:00:00

abstract：:Although statistical methodology is well-developed for comparing diagnostic tests in terms of their sensitivity and specificity, comparative inference about predictive values is not. In this paper, we consider the analysis of studies comparing operating characteristics of two diagnostic tests that are measured on all ...

journal_title：Statistics in medicine

authors： Kwak M,Um SW,Jung SH

更新日期：2015-07-10 00:00:00

abstract：:In population-based case-control studies, an attempt is made to identify all incident cases diagnosed in a specified population during a fixed time interval. Assuming that this goal is met allows one to obtain measures of risk other than relative risks. In this paper, we describe three approaches to estimate exposure-...

journal_title：Statistics in medicine

authors： Benichou J,Wacholder S

更新日期：1994-03-15 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：:Matched-pair designs have been commonly employed in diagnostic, epidemiologic and laboratory studies. For estimation of a ratio of two marginal probabilities in matched-pair data, a Wald-type logarithmic method is computationally simple, but an actual coverage rate is known to be smaller than a nominal one and a lengt...

journal_title：Statistics in medicine

authors： Nam JM

更新日期：2009-10-15 00:00:00

abstract：:Multivariate outcomes measured longitudinally over time are common in medicine, public health, psychology and sociology. The typical (saturated) longitudinal multivariate regression model has a separate set of regression coefficients for each outcome. However, multivariate outcomes are often quite similar and many out...

journal_title：Statistics in medicine

authors： Jia J,Weiss RE

更新日期：2009-06-15 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：:We propose a new, less costly, design to test the equivalence of digital versus analogue mammography in terms of sensitivity and specificity. Because breast cancer is a rare event among asymptomatic women, the sample size for testing equivalence of sensitivity is larger than that for testing equivalence of specificity...

journal_title：Statistics in medicine

authors： Baker SG,Connor RJ,Kessler LG

更新日期：1998-10-15 00:00:00

abstract：:Weak measurement of epidemiologic exposures is an impediment to appreciation of the effects of those exposures. This paper discusses two strategies to assess the true effects of weakly measured exposure. The first is to use external information about the extent of mismeasurement to adjust estimates of the effects of e...

journal_title：Statistics in medicine

authors： Marshall JR

更新日期：1989-09-01 00:00:00

abstract：:A new goodness-of-fit test for the logistic regression model is proposed. It exploits the property of this model that when it is correct, i.e. not misspecified, the parameter estimates are (asymptotically) invariant under reweighting the observations by weights wi that are a function of the binary (0/1) outcomes yi. M...

journal_title：Statistics in medicine

authors： Nagelkerke N,Smits J,le Cessie S,van Houwelingen H

更新日期：2005-01-15 00:00:00

abstract：:The two tailed Fisher's exact P value is extremely sensitive to small perturbations in 2 x 2 contingency tables. An example indicates that a 1 per cent increase in the denominator of one treatment group results in a 32 per cent drop in the exact P value, but a mere 0.1 per cent decrease in the treatment success rate. ...

journal_title：Statistics in medicine

authors： Dupont WD

更新日期：1986-11-01 00:00:00

abstract：:Down's syndrome screening is currently carried out using a combination of biochemical markers measured in maternal serum samples; these include MSAFP, Total hCG, uE3 and Free beta-hCG. Recently a number of papers have compared the effectiveness of different combinations of these markers. Some recommend MSAFP, Total hC...

journal_title：Statistics in medicine

authors： Dunstan FD,Gray JC,Nix AB,Reynolds T

更新日期：1997-07-15 00:00:00

abstract：:In this article we develop flexible regression models in two respects to evaluate the influence of the covariate variables on the mixed Poisson and continuous responses and to evaluate how the correlation between Poisson response and continuous response changes over time. A scenario for dealing with regression models ...

journal_title：Statistics in medicine

authors： Yang Y,Kang J,Mao K,Zhang J

更新日期：2007-09-10 00:00:00