ISSN:0277-6715    

DOI:10.1002/sim.4780140102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractWe review some recent statistical methods for examining geographic patterns of disease incidence for the presence of clusters. General methods search for clusters throughout the study area and then assess the statistical significance of any clusters detected. Focused methods check for elevated incidence rates close to prespecified locations of putative sources of hazard. We apply the methods to leukaemia incidence data for children aged 0–15 years in Sweden (1980–1990), particularly in reference to locations of nuclear power facilities. Unlike some other studies, notably in the United Kingdom, we do not find any significant clust

ISSN:0277-6715    

DOI:10.1002/sim.4780140103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractI derive two new statistics,IpopandI*pop, that adjust Moran'sIto study clustering of disease cases in areas (for example, counties) with different, known population densities. A simulation of Lyme disease in Georgia suggests that these new statistics can be more powerful than those currently in use. This is because they consider both spatial pattern and non‐binomial variance in rates as evidence supporting disease cluster

ISSN:0277-6715    

DOI:10.1002/sim.4780140104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractWe present a direct approach for correcting the acquired immunodeficiency syndrome (AIDS) incidence data for reporting delays, based on a non‐parametric method for the analysis of right truncated data. We show that the proposed method when applied for grouped data is equivalent to three other published methods. We give a simple formula for the variance of the estimated AIDS incidence. Both estimator and variance are assessed in a simulation study. It is important for the estimation of AIDS incidence in the last quarter of the period under consideration to use month rather than quarter or half‐year as the time unit for the analyses. The method is illustrated using data from the United States Centers for Disease Cont

ISSN:0277-6715    

DOI:10.1002/sim.4780140105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractWe review currently known results concerning the estimation of an ‘immune’ or ‘cured’ proportion, and testing for the presence of immunes, in censored survival data, suggesting that a firm theoretical foundation now exists for analysis. Two types of estimators, parametric and non‐parametric, are discussed and compared with respect to their theoretical properties, and, by simulation, with respect to their small sample behaviour. Both estimators have advantages and drawbacks, but together provide powerful tools for the perceptive analysis of survival data with, or even without, immune in

ISSN:0277-6715    

DOI:10.1002/sim.4780140106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe prevented fraction(PF)is the proportion of disease occurrence in a population averted due to a protective risk factor or public health intervention. ThePFis not equivalent to the population attributable risk(AR). TheARis appropriate for epidemiologic studies of disease etiology, and for estimating the potential impact of modifying risk factor prevalence. ThePFmore directly measures the impact of public health interventions, however, and thus is an important evaluation tool. We derived the variance of the estimatedPFby using maximum likelihood theory for cross‐sectional studies. We used simulations to compare the performance of confidence intervals based on various transformations of the estimatedPF. The logit transformation was the best choice whenPF≥ 0·3, whereas the untransformed estimate was best whenPF<0·3. We present formulae for hypothesis testing and sample size calculations, discuss the issues of interaction and confounding and give two estimators adjusted for confou

ISSN:0277-6715    

DOI:10.1002/sim.4780140107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractNeural networks have received considerable attention recently, mostly by non‐statisticians. They are considered by many to be very promising tools for classification and prediction. In this paper we present an approach to modelling censored survival data using the input—output relationship associated with a simple feed‐forward neural network as the basis for a non‐linear proportional hazards model. This approach can be extended to other models used with censored survival data. The proportional hazards neural network parameters are estimated using the method of maximum likelihood. These maximum likelihood based models can be compared, using readily available techniques such as the likelihood ratio test and the Akaike criterion. The neural network models are illustrated using data on the survival of men with prostatic carcinoma. A method of interpreting the neural network predictions based on the factorial contrasts is pr

ISSN:0277-6715    

DOI:10.1002/sim.4780140108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractWe present an estimate of the kappa‐coefficient of agreement between two methods of rating based on matched pairs of binary responses and show that the estimate depends on the common intraclass correlation coefficient between the pairs. Via Monte Carlo simulation, we investigate power of the test of significance on kappa, and the large sample bias and variance of its maximum likelihood estimato

ISSN:0277-6715    

DOI:10.1002/sim.4780140109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

ISSN:0277-6715    

DOI:10.1002/sim.4780140110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

ISSN:0277-6715    

DOI:10.1002/sim.4780140111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY