Abstract:
:Day and Walter derived methods of joint maximum likelihood estimation for the sojourn time distribution and the false negative rate for a screening programme. Their methods are not directly applicable to a programme which uses alternate screening by two modalities whose sojourn times and false negative rates will differ. A modification is proposed and the results applied to data from the Edinburgh Randomised Trial of Breast Cancer Screening. This enables the effects of mammography and clinical examination to be separated. It is estimated that in a programme using both modalities 79 per cent of tumours arising in regularly screened women would be detected by screening and if the clinical examination were omitted this figure would be reduced by 5 per cent. The confidence intervals are, however, quite wide.
journal_name
Stat Medjournal_title
Statistics in medicineauthors
Alexander FEdoi
10.1002/sim.4780080611subject
Has Abstractpub_date
1989-06-01 00:00:00pages
743-55issue
6eissn
0277-6715issn
1097-0258journal_volume
8pub_type
杂志文章abstract::With considerable current interest in longitudinal epidemiologic studies, little is available regarding sample size requirements. This paper considers a method for analysis of longitudinal data, where one compares the mean rates of change for two or more groups, and proposes a statistic for use in determining sample s...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780090414
更新日期:1990-04-01 00:00:00
abstract::Analyses to compare non-randomized groups are more and more common in both post hoc analyses of randomized clinical trials data and in analyses of long-term observational data. In such cases, it is quite likely that there are unknown or uncollected sources of heterogeneity in event rates. Research has shown that an un...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1795
更新日期:2004-07-15 00:00:00
abstract::Although prostate cancer and benign prostatic hyperplasia are major health problems in U.S. men, little is known about the early stages of the natural history of prostate disease. A molecular biomarker called prostate specific antigen (PSA), together with a unique longitudinal bank of frozen serum, now allows a histor...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780130520
更新日期:1994-03-15 00:00:00
abstract::We describe rank-based approaches to assess principal stratification treatment effects in studies where the outcome of interest is only well-defined in a subgroup selected after randomization. Our methods are sensitivity analyses, in that estimands are identified by fixing a parameter and then we investigate the sensi...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5849
更新日期:2013-11-20 00:00:00
abstract::There has been substantial statistical literature in the last several decades on assessing agreement, and coverage probability approach was selected as a preferred index for assessing and improving measurement agreement in a core laboratory setting. With this approach, a satisfactory agreement is based on pre-specifie...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6903
更新日期:2016-08-15 00:00:00
abstract::The sojourn time, time spent in the preclinical detectable phase (PCDP) for chronic diseases, for example, breast cancer, plays an important role in the design and assessment of screening programmes. Traditional methods to estimate it usually assume a uniform incidence rate of preclinical disease from a randomized con...
journal_title:Statistics in medicine
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1002/sim.4780141404
更新日期:1995-07-30 00:00:00
abstract::The need for resource-intensive laboratory assays to assess exposures in many epidemiologic studies provides ample motivation to consider study designs that incorporate pooled samples. In this paper, we consider the case in which specimens are combined for the purpose of determining the presence or absence of a pool-w...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4426
更新日期:2012-09-28 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::We propose a probability distribution for an equivalence class of classification trees (that is, those that ignore the value of the cutpoints but retain tree structure). This distribution is parameterized by a central tree structure representing the true model, and a precision or concentration coefficient representing...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19990330)18:6<727::aid-sim
更新日期:1999-03-30 00:00:00
abstract::A model is developed to estimate the effect of covariate imbalance on the size of a test of treatment efficacy in randomized clinical trials comparing two treatments when dispersion parameters are known. It is concluded that tests of homogeneity on the covariates should not be performed, that covariate imbalance is ju...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780080410
更新日期:1989-04-01 00:00:00
abstract::Methodology for the meta-analysis of individual patient data with survival end-points is proposed. Motivated by questions about the reliance on hazard ratios as summary measures of treatment effects, a parametric approach is considered and percentile ratios are introduced as an alternative to hazard ratios. The genera...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4086
更新日期:2010-12-20 00:00:00
abstract::Prevalent sampling is frequently a convenient and economical sampling technique for the collection of time-to-event data and thus is commonly used in studies of the natural history of a disease. However, it is biased by design because it tends to recruit individuals with longer survival times. This paper considers est...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7184
更新日期:2017-04-15 00:00:00
abstract::The explanation of heterogeneity plays an important role in meta-analysis. The random effects meta-regression model allows the inclusion of trial-specific covariates which may explain a part of the heterogeneity. We examine the commonly used tests on the parameters in the random effects meta-regression with one covari...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1482
更新日期:2003-09-15 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
pub_type: 杂志文章
doi:10.1002/sim.3706
更新日期:2010-05-10 00:00:00
abstract::Sequential analysis is frequently employed to address ethical and financial issues in clinical trials. Sequential analysis may be performed using standard group sequential designs, or, more recently, with adaptive designs that use estimates of treatment effect to modify the maximal statistical information to be collec...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4156
更新日期:2011-05-20 00:00:00
abstract::Technologic advances give rise to new tests for detecting disease in many fields, including cancer and sexually transmitted disease. Before a new disease screening test is approved for public use, its accuracy should be shown to be better than or at least not inferior to an existing test. Standards do not yet exist fo...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1058
更新日期:2002-03-30 00:00:00
abstract::This paper reviews Bayesian strategies for monitoring clinical trial data. It focuses on a Bayesian stochastic curtailment method based on the predictive probability of observing a clinically significant outcome at the scheduled end of the study given the observed data. The proposed method is applied to derive efficac...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2204
更新日期:2006-07-15 00:00:00
abstract::In medical and health studies, heterogeneities in clustered count data have been traditionally modeled by positive random effects in Poisson mixed models; however, excessive zeros often occur in clustered medical and health count data. In this paper, we consider a three-level random effects zero-inflated Poisson model...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3619
更新日期:2009-08-15 00:00:00
abstract::When estimating the probability of natural conception from observational data on couples with an unfulfilled child wish, the start of assisted reproductive therapy (ART) is a competing event that cannot be assumed to be independent of natural conception. In clinical practice, interest lies in the probability of natura...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6280
更新日期:2014-11-20 00:00:00
abstract::We propose a joint model for a time-to-event outcome and a quantile of a continuous response repeatedly measured over time. The quantile and survival processes are associated via shared latent and manifest variables. Our joint model provides a flexible approach to handle informative dropout in quantile regression. A M...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6393
更新日期:2015-03-30 00:00:00
abstract::The power to detect a treatment effect in cluster randomized trials can be increased by increasing the number of clusters. An alternative is to include covariates into the regression model that relates treatment condition to outcome. In this paper, formulae are derived in order to evaluate both strategies on basis of ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2297
更新日期:2006-08-15 00:00:00
abstract::Although hypertension is regarded as a causal factor for coronary heart disease (CHD) a reduction in the risk of CHD as a result of lowering blood pressure in mild hypertension could not be demonstrated. This conclusion is based on an overview analysis of all published randomized trials in mild hypertension, including...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780071104
更新日期:1988-11-01 00:00:00
abstract::Bioequivalence assessment is an issue of great interest. Development of statistical methods for assessing bioequivalence is an important area of research for statisticians. Bioequivalence is usually determined based on the normal distribution. We relax this assumption and develop a semi-parametric mixed model for bioe...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2620
更新日期:2007-03-15 00:00:00
abstract::Randomized clinical trial designs commonly include one or more planned interim analyses. At these times an external monitoring committee reviews the accumulated data and determines whether it is scientifically and ethically appropriate for the study to continue. With failure-time endpoints, it is common to schedule an...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.843
更新日期:2001-07-30 00:00:00
abstract::We propose a joint model to analyze the structure and intensity of the association between longitudinal measurements of an ordinal marker and time to a relevant event. The longitudinal process is defined in terms of a proportional-odds cumulative logit model. Time-to-event is modeled through a left-truncated proportio...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7065
更新日期:2016-12-10 00:00:00
abstract::We discuss some of the statistical approaches to the design and analysis of phase I clinical trials in cancer. An attempt is made to identify the issues, particular to this type of trial, that should be addressed by an appropriate methodology. A brief review of schemes currently in use is provided together with our vi...
journal_title:Statistics in medicine
pub_type: 杂志文章,评审
doi:10.1002/sim.4780101104
更新日期:1991-11-01 00:00:00
abstract::In this paper we present a simple method for constructing (1- alpha)100 per cent confidence intervals for binomial proportions with near nominal coverage for all underlying proportion parameters on the unit interval. This new method uses, with a slight modification, the standard normal approximation technique taught i...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2469
更新日期:2006-11-15 00:00:00
abstract::Assay sensitivity has been proposed as a criterion for including psychiatric clinical outcome studies in meta-analyses. The authors assess the performance of assay sensitivity as a method for determining study appropriateness for meta-analysis by calculating expected standard drug vs placebo effect sizes for various c...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2240
更新日期:2006-03-30 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::It is naive and incorrect to use the proportions of successful operations to compare the performance of surgeons because the patients' risk profiles are different. In this paper, we explore the use of risk-adjusted procedures to compare the performance of surgeons. One such risk-adjusted statistic is the standardized ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7310
更新日期:2017-07-20 00:00:00