Abstract:
:A three-component, competing-risk mortality model, developed for animal survival data, fits human life table data for all ages over a range of mean life spans from 16 to 74 years. The competing risks are a novel exponentially-decreasing hazard, dominant during immaturity; a constant hazard, dominant during adulthood; and an exponentially increasing Gompertzian hazard, dominant during senescence. By fitting the model to a specific life table using non-linear techniques, estimates of the five model parameters and their standard errors obtain; the proportion of deaths expected from each hazard alone may then be calculated. Preliminary analysis of 13 life tables indicates that for human populations under heavy stress, with very short mean life spans of about 20 years, the three hazard components account for roughly equal numbers of deaths; for modern populations, with mean life spans of about 75 years, nearly all deaths are due to the hazard of senescence. Factor analysis of the correlation matrix of parameter values for the 13 populations shows a two-factor structure. One factor involves only the multiplicative constants (initial values) of the three hazards, but not the hazard rates of change; the second factor involves only the parameter of the immaturity hazard and the rate of acceleration of the senescence hazard, but not the constant hazard nor the multiplicative constant (initial value) of the senescence hazard.
journal_name
Stat Medjournal_title
Statistics in medicineauthors
Siler Wdoi
10.1002/sim.4780020309subject
Has Abstractpub_date
1983-07-01 00:00:00pages
373-80issue
3eissn
0277-6715issn
1097-0258journal_volume
2pub_type
杂志文章abstract::The additional time to complete a three-period two-treatment (3P2T) cross-over trial may cause a greater number of patient dropouts than with a two-period trial. This paper develops maximum likelihood (ML), single imputation and multiple imputation missing data analysis methods for the 3P2T cross-over designs. We use ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(SICI)1097-0258(19960130)15:2<127::AID-SIM
更新日期:1996-01-30 00:00:00
abstract::Funnel plots are widely used to visualize grouped data, for example, in institutional comparison. This paper extends the concept to a multi-level setting, displaying one level at a time, adjusted for the other levels, as well as for covariates at all levels. These level-adjusted funnel plots are based on a Markov chai...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5677
更新日期:2014-09-20 00:00:00
abstract::Non-tumor cell-based model systems have recently gained interest in pharmacogenetic research as a hypothesis generating tool. The hypotheses generated from these model systems can be followed up in functional studies, or tested in individuals taking the same investigational agents. The current cellular phenotypes (e.g...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3649
更新日期:2009-09-20 00:00:00
abstract::The problem of testing symmetry about zero has a long and rich history in the statistical literature. We introduce a new test that sequentially discards observations whose absolute value is below increasing thresholds defined by the data. McNemar's statistic is obtained at each threshold and the largest is used as the...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5384
更新日期:2012-11-20 00:00:00
abstract::Reference ranges which take time (such as age) into account are often required in medicine, but simple, systematic and efficient statistical methods for constructing them are lacking. A method is described which is based on low order polynomial curves (linear, quadratic or occasionally cubic), together with guidelines...
journal_title:Statistics in medicine
pub_type: 临床试验,杂志文章,多中心研究
doi:10.1002/sim.4780100502
更新日期:1991-05-01 00:00:00
abstract::The general linear mixed model provides a useful approach for analysing a wide variety of data structures which practising statisticians often encounter. Two such data structures which can be problematic to analyse are unbalanced repeated measures data and longitudinal data. Owing to recent advances in methods and sof...
journal_title:Statistics in medicine
pub_type: 杂志文章,评审
doi:10.1002/(sici)1097-0258(19971030)16:20<2349::aid-s
更新日期:1997-10-30 00:00:00
abstract::The statistical analysis of panel count data has recently attracted a great deal of attention, and a number of approaches have been developed. However, most of these approaches are for situations where the observation and follow-up processes are independent of the underlying recurrent event process unconditional or co...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5724
更新日期:2013-07-30 00:00:00
abstract::Cost data that arise in the evaluation of health care technologies usually exhibit highly skew, heavy-tailed and, possibly, multi-modal distributions. Distribution-free methods for analysing these data, such as the bootstrap, or those based on the asymptotic normality of sample means, may often lead to inefficient or ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2012
更新日期:2005-10-30 00:00:00
abstract::Mesothelioma is a rare cancer caused by exposure to asbestos. Belgium has a known long history of asbestos production, resulting in one of the highest mesothelioma mortality rates worldwide. While the production of asbestos has stopped completely, the long latency period of mesothelioma, which can fluctuate between 20...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8697
更新日期:2020-11-20 00:00:00
abstract::Much has been published on various aspects of data analysis and reporting from clinical trials within the biopharmaceutical environment. This ranges from regulatory guidelines on the format and content of registration dossiers to recommendations on data presentation and the statistical methodologies that are appropria...
journal_title:Statistics in medicine
pub_type: 杂志文章,评审
doi:10.1002/(sici)1097-0258(19980815/30)17:15/16<1829:
更新日期:1998-08-15 00:00:00
abstract::Phase II and phase III trials play a crucial role in drug development programs. They are costly and time consuming and, because of high failure rates in late development stages, at the same time risky investments. Commonly, sample size calculation of phase III is based on the treatment effect observed in phase II. The...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6624
更新日期:2016-01-30 00:00:00
abstract::Residuals in normal regression are used to assess a model's goodness-of-fit (GOF) and discover directions for improving the model. However, there is a lack of residuals with a characterized reference distribution for censored regression. In this article, we propose to diagnose censored regression with normalized rando...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8852
更新日期:2020-12-13 00:00:00
abstract::The serial dilution assay (for example, an in vitro antimicrobic susceptibility test or a serum antibody titer assay) is an important technique in biomedical research. The structure of the experiment forces grouping of the threshold concentrations into intervals. Statistical methods to analyse threshold concentrations...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780070410
更新日期:1988-04-01 00:00:00
abstract::This paper gives a standard error for Cohen's Kappa, conditional on the margins of the observed r x r table. An explicit formula is given for the 2 x 2 table, and a procedure for the more general situation. A parsimonious log-linear model is suggested for the general case and an approximate confidence interval for kap...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780100512
更新日期:1991-05-01 00:00:00
abstract::This paper presents a general approach for simultaneously assessing, from serial data, diagnostic consistency, interrater reliability and incidence of a strictly progressive disease. Observed data are viewed as incomplete: diagnostic errors are not distinguished from true diagnoses. We introduce a broad class of model...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780070306
更新日期:1988-03-01 00:00:00
abstract::Estimating the causal effect of quitting smoking on time to death or first myocardial infarction requires that one control for the differences in risk factors between individuals who elect to quite at each time t versus those who elect to continue smoking at time t. In this paper we examine the limitations of standard...
journal_title:Statistics in medicine
pub_type: 杂志文章,多中心研究
doi:10.1002/sim.4780121707
更新日期:1993-09-15 00:00:00
abstract::Standard methods for analysing survival data or case-control data normally concern factors affecting a subject as a whole. However, in a study of a condition that might develop in one or both of a pair of bodily organs information on response and on covariates may be available for each separately. This information can...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780070509
更新日期:1988-05-01 00:00:00
abstract::Assessment of equivalence or non-inferiority in accuracy between two diagnostic procedures often involves comparisons of paired areas under the receiver operating characteristic (ROC) curves. With some pre-specified clinically meaningful limits, the current approach to evaluating equivalence is to perform the two one-...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2358
更新日期:2006-04-15 00:00:00
abstract::The availability of large data sets together with the growth in power and storage capabilities of computers have made the analysis of the spatial distribution of disease rates an increasingly important tool in public health research. Use of existing geographic divisions or groupings tends to result either in unstable ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780121916
更新日期:1993-10-01 00:00:00
abstract::Measures that quantify the impact of heterogeneity in univariate meta-analysis, including the very popular I(2) statistic, are now well established. Multivariate meta-analysis, where studies provide multiple outcomes that are pooled in a single analysis, is also becoming more commonly used. The question of how to quan...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5453
更新日期:2012-12-20 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
pub_type: 杂志文章
doi:10.1002/sim.4125
更新日期:2011-03-30 00:00:00
abstract::A trial of Duchenne muscular dystrophy involved tracking boys of all ages through a one-year baseline period, followed by a one-year trial of leucine versus placebo treatment. In this paper we develop a model for a total-muscle-strength score that uses the data of the extended baseline period in the evaluation of the ...
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.4780050304
更新日期:1986-05-01 00:00:00
abstract::In genetic association studies, it is typically thought that genetic variants and environmental variables jointly will explain more of the inheritance of a phenotype than either of these two components separately. Traditional methods to identify gene-environment interactions typically consider only one measured enviro...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5444
更新日期:2013-01-30 00:00:00
abstract::Incomplete and unbalanced multivariate data often arise in longitudinal studies due to missing or unequally-timed repeated measurements and/or the presence of time-varying covariates. A general approach to analysing such data is through maximum likelihood analysis using a linear model for the expected responses, and s...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780070132
更新日期:1988-01-01 00:00:00
abstract::Medical costs data with administratively censored observations often arise in cost-effectiveness studies of treatments for life-threatening diseases. Mean of medical costs incurred from the start of a treatment until death or a certain time point after the implementation of treatment is frequently of interest. In many...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1556
更新日期:2004-11-15 00:00:00
abstract::Meta-analysis is the methodology for combining findings from similar research studies asking the same question. When the question of interest involves multiple outcomes, multivariate meta-analysis is used to synthesize the outcomes simultaneously taking into account the correlation between the outcomes. Likelihood-bas...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4327
更新日期:2011-10-30 00:00:00
abstract::The Spearman (rho(s)) and Kendall (tau) rank correlation coefficient are routinely used as measures of association between non-normally distributed random variables. However, confidence limits for rho(s) are only available under the assumption of bivariate normality and for tau under the assumption of asymptotic norma...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2547
更新日期:2007-02-10 00:00:00
abstract::Mediation analysis is a standard approach to understanding how and why an intervention works in social and medical sciences. However, the presence of missing data, especially missing not at random data, poses a great challenge for the applicability of this approach in practice. Current methods for handling such missin...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7413
更新日期:2017-11-10 00:00:00
abstract::One is often interested in the ratio of two variables, for example in genetics, assessing drug effectiveness, and in health economics. In this paper, we derive an explicit geometric solution to the general problem of identifying the two tangents from an arbitrary external point to an ellipse. This solution permits num...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3398
更新日期:2008-12-10 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
pub_type: 杂志文章
doi:10.1002/sim.719
更新日期:2001-04-30 00:00:00