Abstract:
:Recent studies have indicated variation in the infectivity beta of HIV among heterosexual couples. We represent this heterogeneity by modelling beta as a random variable. Using data on the number of contacts and seroconversion of couples, we fit the model by maximum-likelihood estimation with a beta distribution and a discrete distribution for beta. The estimates indicate the heterogeneity is extreme. The limitations of the model and the implications of the results for epidemiologic spread and further research are discussed.
journal_name
Stat Medjournal_title
Statistics in medicineauthors
Wiley JA,Herschkorn SJ,Padian NSdoi
10.1002/sim.4780080110subject
Has Abstractpub_date
1989-01-01 00:00:00pages
93-102issue
1eissn
0277-6715issn
1097-0258journal_volume
8pub_type
杂志文章abstract::Proportional hazards (or Cox) regression is a popular method for modelling the effects of prognostic factors on survival. Use of cubic spline functions to model time-by-covariate interactions in Cox regression allows investigation of the shape of a possible covariate-time dependence without having to specify a specifi...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780131007
更新日期:1994-05-30 00:00:00
abstract::In longitudinal studies, missing observations occur commonly. It has been well known that biased results could be produced if missingness is not properly handled in the analysis. Authors have developed many methods with the focus on either incomplete response or missing covariate observations, but rarely on both. The ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5536
更新日期:2013-02-28 00:00:00
abstract::Data on alcohol availability and problems in all cities in Los Angeles County were collected from several different sources and linked together to form a Local Alcohol Availability Database (LAAD). The two major purposes of the project are to provide a city-level alcohol availability and alcohol-related problems datab...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780140517
更新日期:1995-03-15 00:00:00
abstract::The authors measure the efficacy of three methods for predicting the time to infection for susceptible individuals in a population undergoing an HIV epidemic. The methods differ in whether they require detailed information of the contact network and whether they require knowledge of the initial source of infection. Ef...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780130107
更新日期:1994-01-15 00:00:00
abstract::Methodology for causal inference based on propensity scores has been developed and popularized in the last two decades. However, the majority of the methodology has concentrated on binary treatments. Only recently have these methods been extended to settings with multi-valued treatments. We propose a number of discret...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2095
更新日期:2005-07-30 00:00:00
abstract::Several large-sample confidence intervals for the ratio of independent binomial proportions are compared in terms of exact coverage probability and width. A non-iterative approximate Bayesian interval is derived and its frequency properties are superior to all of the non-iterative confidence intervals considered. The ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3376
更新日期:2008-11-20 00:00:00
abstract::Meta-analysis to investigate the joint effect of multiple factors in the aetiology of a disease is of increasing importance in epidemiology. This task is often challenging in practice, because studies typically concentrate on studying the effect of only one exposure, sometimes may report the interaction between two ex...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2689
更新日期:2006-12-30 00:00:00
abstract::Longitudinal designs are important in medical research and in many other disciplines. Complete longitudinal studies, in which each subject is evaluated at each measurement occasion, are often very expensive and motivate a search for more efficient designs. Recently developed statistical methods foster the use of inten...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780111411
更新日期:1992-10-01 00:00:00
abstract:BACKGROUND:It has been recommended that onset of antidepressant action be assessed using survival analyses with assessments taken at least twice per week. However, such an assessment schedule is problematic to implement. The present study assessed the feasibility of comparing onset of action between treatments using a ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2309
更新日期:2006-07-30 00:00:00
abstract::We present methods for binomial regression when the outcome is determined using the results of a single diagnostic test with imperfect sensitivity and specificity. We present our model, illustrate it with the analysis of real data, and provide an example of WinBUGS program code for performing such an analysis. Conditi...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1656
更新日期:2004-04-15 00:00:00
abstract::This paper describes the Stoke Index which has been designed to give a global measure of disease activity in rheumatoid arthritis. The index is based on two objective laboratory measurements, one subjective and two semi-objective clinical measurements, chosen from 13 measurements using clinical judgement. Variable sel...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780121206
更新日期:1993-06-30 00:00:00
abstract::Selection of dose for cancer patients treated with radiation therapy (RT) must balance the increased efficacy with the increased toxicity associated with higher dose. Historically, a single dose has been selected for a population of patients (e.g., all stage III non-small cell lung cancer). However, the availability o...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6285
更新日期:2014-12-30 00:00:00
abstract::Optimal prevention and treatment strategies for a disease of multiple causes, such as pneumonia, must be informed by the population distribution of causes among cases, or cause-specific case fractions (CSCFs). CSCFs may further depend on additional explanatory variables. Existing methodological literature in disease e...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8804
更新日期:2021-02-20 00:00:00
abstract::The induced smoothing technique overcomes the difficulties caused by the non-smoothness in rank-based estimating functions for accelerated failure time models, but it is only natural when the estimating function has Gehan's weight. For a general weight, the induced smoothing method does not provide smooth estimating f...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6415
更新日期:2015-04-30 00:00:00
abstract::Comparative effectiveness research represents the kind of research that arguably more directly affects clinical practice and policy. It includes observational studies, clinical trials, and systematic syntheses of existing literature. In this commentary, I argue for the ongoing and critical role of randomization in com...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5400
更新日期:2012-11-10 00:00:00
abstract::We estimate a Cox proportional hazards model where one of the covariates measures the level of a subject's cognitive functioning by grading the total score obtained by the subject on the items of a questionnaire. A case study is presented where the sample includes partial respondents, who did not answer some questionn...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3773
更新日期:2010-01-30 00:00:00
abstract::A method for detecting deviations from the Loewe additive drug combination reference model for in vitro drug combination experimentation is described. It is often difficult to fit a response surface model to drug combination data, especially in situations where the experimental design contains a sparse set of combinat...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5905
更新日期:2013-12-20 00:00:00
abstract::Recently, Wu and Follmann developed summary measures to adjust for informative drop-out in longitudinal studies where drop-out depends on the underlying true value of the response. In this paper we evaluate these procedures in the common situation where drop-out depends on the observed responses. We also discuss vario...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/1097-0258(20010115)20:1<93::aid-sim655>3.0
更新日期:2001-01-15 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
pub_type: 杂志文章
doi:10.1002/sim.4780120104
更新日期:1993-01-15 00:00:00
abstract::Novel methodology is implemented to assess the predictive power of covariate information associated with sequential binary events. Logistic models are first fitted on the basis of a subset of the observations and then evaluated sequentially on the rest. The probabilistic forecasts are compared to the outcomes via a sc...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(SICI)1097-0258(19961030)15:20<2149::AID-S
更新日期:1996-10-30 00:00:00
abstract::Population dynamic models, commonly used tools in the study of epidemics and other complex population processes, are implicit non-linear mathematical equations. Inference based on such models can be difficult due to the problems associated with high dimensional parameters that may be non-identified and complex likelih...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1258
更新日期:2002-12-15 00:00:00
abstract::The Box-Cox power exponential (BCPE) distribution, developed in this paper, provides a model for a dependent variable Y exhibiting both skewness and kurtosis (leptokurtosis or platykurtosis). The distribution is defined by a power transformation Y(nu) having a shifted and scaled (truncated) standard power exponential ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1861
更新日期:2004-10-15 00:00:00
abstract::In genetic and genomic studies, gene-environment (G×E) interactions have important implications. Some of the existing G×E interaction methods are limited by analyzing a small number of G factors at a time, by assuming linear effects of E factors, by assuming no data contamination, and by adopting ineffective selection...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6609
更新日期:2015-12-30 00:00:00
abstract::This paper considers the problem of selecting a set of regressors when the response variable is distributed according to a specified parametric model and observations are censored. Under a Bayesian perspective, the most widely used tools are Bayes factors (BFs), which are undefined when improper priors are used. In or...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6249
更新日期:2014-11-20 00:00:00
abstract::Increasing numbers of economic evaluations are conducted alongside randomised controlled trials. Such studies include factorial trials, which randomise patients to different levels of two or more factors and can therefore evaluate the effect of multiple treatments alone and in combination. Factorial trials can provide...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7322
更新日期:2017-08-15 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
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19971015)16:19<2229::aid-s
更新日期:1997-10-15 00:00:00
abstract::The original article to which this Correction refers was published in Statistics in Medicine 2000 19(14): 1901-1914. ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/1097-0258(20001115)19:21<3017::aid-sim785>
更新日期:2000-11-15 00:00:00
abstract::Combining multiple markers can improve classification accuracy compared with using a single marker. In practice, covariates associated with markers or disease outcome can affect the performance of a biomarker or biomarker combination in the population. The covariate-adjusted receiver operating characteristic (ROC) cur...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7274
更新日期:2017-07-10 00:00:00
abstract::We examine Goodman and Kruskal's lambda using Efron's approach to regression and analysis of variance (ANOVA) for zero-one outcome data. For a binary response cross-classified by a single nominal predictor, we present a computationally simple ANOVA table in which lambda is analogous to Pearson's R-square. We character...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780080511
更新日期:1989-05-01 00:00:00
abstract::Meta-analyses pooling continuous outcomes can use mean differences (MD), standardized MD (MD in pooled standard deviation units, SMD), or ratio of arithmetic means (RoM). Recently, ratio of geometric means using ad hoc (RoGM (ad hoc) ) or Taylor series (RoGM (Taylor) ) methods for estimating variances have been propos...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4501
更新日期:2012-07-30 00:00:00