International Journal of Biostatistics最新文献_第9页

Some Variants of the Backcalculation Method for Estimation of Disease Incidence: An Application to Multiple Sclerosis Data from the Faroe Islands 估计疾病发病率的反计算方法的一些变体:法罗群岛多发性硬化症数据的应用

IF 1.2 4区数学

International Journal of Biostatistics Pub Date : 2005-06-09 DOI: 10.2202/1557-4679.1002

N. Jewell, B. Lu

{"title":"Some Variants of the Backcalculation Method for Estimation of Disease Incidence: An Application to Multiple Sclerosis Data from the Faroe Islands","authors":"N. Jewell, B. Lu","doi":"10.2202/1557-4679.1002","DOIUrl":"https://doi.org/10.2202/1557-4679.1002","url":null,"abstract":"Backcalculation is a technique that was originally developed for the study of HIV incidence. Here we introduce some variants of the estimation technique that allow for (i) correlation of the unobserved disease incidence counts, and (ii) the use of a smoothing step as part of the maximizing step in the EM algorithm to reduce instability due to small diagnosis counts. Both of these issues can be important in the analysis of small \"epidemics.\" In addition, identification of correlation between diagnosis counts provides indirect evidence of correlation among unobserved incidence counts, hinting at the possibility of an infectious agent. We illustrate the ideas by reconstructing an incidence intensity function for the onset of multiple sclerosis, using data from the Faroe Islands. Previously, this data had been examined statistically, by Joseph, Wolfson & Wolfson (1990), to address the issue of infectiousness of multiple sclerosis. We argue that the incidence function cannot directly shed light on the enigmatic origin of multiple sclerosis in the Faroe Islands during World War II, and, in particular, cannot discriminate between hypotheses of an infectious or environmental agent.","PeriodicalId":50333,"journal":{"name":"International Journal of Biostatistics","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2005-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2202/1557-4679.1002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68714703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

A Weighted Risk Set Estimator for Survival Distributions in Two-Stage Randomization Designs with Censored Survival Data 带有删节生存数据的两阶段随机化设计中生存分布的加权风险集估计

IF 1.2 4区数学

International Journal of Biostatistics Pub Date : 2005-01-01 DOI: 10.2202/1557-4679.1000

Xiang Guo, A. Tsiatis

引用次数: 4

Frontmatter Frontmatter

IF 1.2 4区数学

International Journal of Biostatistics Pub Date : 1900-01-01 DOI: 10.1515/ijb-2021-frontmatter1

引用次数: 0

Relationship between Derivatives of the Observed and Full Loglikelihoods and Application to Newton-Raphson Algorithm 观测似然与全对数似然的导数关系及其在Newton-Raphson算法中的应用

IF 1.2 4区数学

International Journal of Biostatistics Pub Date : 1900-01-01 DOI: 10.2202/1557-4679.1010

D. Commenges, V. Rondeau

引用次数: 0

Approximate Power and Sample Size Calculations with the Benjamini-Hochberg Method 用Benjamini-Hochberg方法计算近似功率和样本量

IF 1.2 4区数学

International Journal of Biostatistics Pub Date : 1900-01-01 DOI: 10.2202/1557-4679.1018

J. A. Ferreira, A. Zwinderman

引用次数: 25

Statistical Classification of Abnormal Blood Profiles in Athletes 运动员血液异常的统计分类

IF 1.2 4区数学

International Journal of Biostatistics Pub Date : 1900-01-01 DOI: 10.2202/1557-4679.1011

P. Sottas, N. Robinson, S. Giraud, F. Taroni, M. Kamber, P. Mangin, M. Saugy

{"title":"Statistical Classification of Abnormal Blood Profiles in Athletes","authors":"P. Sottas, N. Robinson, S. Giraud, F. Taroni, M. Kamber, P. Mangin, M. Saugy","doi":"10.2202/1557-4679.1011","DOIUrl":"https://doi.org/10.2202/1557-4679.1011","url":null,"abstract":"Blood doping has been challenging the scientific community since the early 1970's, where it was demonstrated that blood transfusion significantly improves physical performance. Here, we present through 3 applications how statistical classification techniques can assist the implementation of effective tests to deter blood doping in elite sports. In particular, we developed a new indirect and universal test of blood doping, called Abnormal Blood Profile Score (ABPS), based on the statistical classification of indirect biomarkers of altered erythropoiesis. Up to 601 hematological profiles have been compiled in a reference database. Twenty-one of them were obtained from blood samples withdrawn from professional athletes convicted of blood doping by other direct tests. Discriminative training algorithms were used jointly with cross-validation techniques to map these labeled reference profiles to target outputs. The strict cross-validation procedure facilitates the adherence to medico-legal standards mandated by the World Anti Doping Agency (WADA). The test has a sensitivity to recombinant erythropoietin (rhEPO) abuse up to 3 times better than current generative models, independently whether the athlete is currently taking rhEPO or has stopped the treatment. The test is also sensitive to any form of blood transfusion, autologous transfusion included. We finally conclude why a probabilistic approach should be encouraged for the evaluation of evidence in anti-doping area of investigation.","PeriodicalId":50333,"journal":{"name":"International Journal of Biostatistics","volume":"2 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2202/1557-4679.1011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68714923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 17

Estimating a Survival Distribution with Current Status Data and High-dimensional Covariates 用当前状态数据和高维协变量估计生存分布

IF 1.2 4区数学

International Journal of Biostatistics Pub Date : 1900-01-01 DOI: 10.2202/1557-4679.1014

A. van der Vaart, M. J. van der Laan

引用次数: 47

Statistical Inference for Variable Importance 变量重要性的统计推断

IF 1.2 4区数学

International Journal of Biostatistics Pub Date : 1900-01-01 DOI: 10.2202/1557-4679.1008

M. J. van der Laan

{"title":"Statistical Inference for Variable Importance","authors":"M. J. van der Laan","doi":"10.2202/1557-4679.1008","DOIUrl":"https://doi.org/10.2202/1557-4679.1008","url":null,"abstract":"Many statistical problems involve the learning of an importance/effect of a variable for predicting an outcome of interest based on observing a sample of $n$ independent and identically distributed observations on a list of input variables and an outcome. For example, though prediction/machine learning is, in principle, concerned with learning the optimal unknown mapping from input variables to an outcome from the data, the typical reported output is a list of importance measures for each input variable. The approach in prediction has been to learn the unknown optimal predictor from the data and derive, for each of the input variables, the variable importance from the obtained fit. In this article we propose a new approach which involves for each variable separately 1) defining variable importance as a real valued parameter, 2) deriving the efficient influence curve and thereby optimal estimating function for this parameter in the assumed (possibly nonparametric) model, and 3) develop a corresponding double robust locally efficient estimator of this variable importance, obtained by substituting for the nuisance parameters in the optimal estimating function data adaptive estimators. We illustrate this methodology in the context of prediction, and obtain in this manner double robust locally optimal estimators of marginal variable importance, accompanied with p-values and confidence intervals. In addition, we present a model based and machine learning approach to estimate covariate-adjusted variable importance. Finally, we generalize this methodology to variable importance parameters for time-dependent variables.","PeriodicalId":50333,"journal":{"name":"International Journal of Biostatistics","volume":"2 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2202/1557-4679.1008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68714461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 163

Properties of the Projected Length of the Curve (PLC) and Area Swept out by the Curve (ASC) Indices for the Receiver Operating Characteristic (SROC) Curve 曲线的投影长度(PLC)和被曲线扫过的面积(ASC)的性质。接收者工作特性(SROC)曲线的指标

IF 1.2 4区数学

International Journal of Biostatistics Pub Date : 1900-01-01 DOI: 10.2202/1557-4679.1096

Xuan Zhang, S. Walter, R. Agnihotram

{"title":"Properties of the Projected Length of the Curve (PLC) and Area Swept out by the Curve (ASC) Indices for the Receiver Operating Characteristic (SROC) Curve","authors":"Xuan Zhang, S. Walter, R. Agnihotram","doi":"10.2202/1557-4679.1096","DOIUrl":"https://doi.org/10.2202/1557-4679.1096","url":null,"abstract":"Several measures have been proposed to summarize the Receiver Operating Characteristic (ROC) curve, including the Projected Length of the Curve (PLC) and the Area Swept out by the Curve (ASC). These indices were first proposed by Lee (Epidemiology 1996; 7:605-611) to avoid certain deficiencies of the traditional Area Under the Curve (AUC) summary measure. More recently meta-analysis methods for assessing diagnostic test accuracy have been developed and the Summary Receiver Operating Characteristic (SROC) curve has been recommended to represent the performance of a diagnostic test. Some properties of the SROC curve were discussed by Walter (Statist. Med. 2002; 21:1237-1256). Here we extend that work to focus on properties of PLC and ASC in the context of SROC curve. Mathematical expressions for these two indices and their variances are derived in terms of the overall diagnostic odds ratio and the magnitude of inter-study heterogeneity in the odds ratio. Expressions for PLC and ASC and their variances are easily computed in homogeneous studies, and their values provide good approximations to the corresponding values for heterogeneous studies in most practical situations. General variances of PLC and ASC are derived by using delta methods, and are found to be smaller if the odds ratio is large. The methods are illustrated using data from two studies, the first being a meta-analysis on the detection of metastases in cervical cancer patients, and the second being a single study of HPV infection and pre-invasive cervical lesions.","PeriodicalId":50333,"journal":{"name":"International Journal of Biostatistics","volume":"5 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2202/1557-4679.1096","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68715363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An Improved Akaike Information Criterion for Generalized Log-Gamma Regression Models 广义Log-Gamma回归模型的改进Akaike信息准则

IF 1.2 4区数学

International Journal of Biostatistics Pub Date : 1900-01-01 DOI: 10.2202/1557-4679.1032

Xiaogang Su, Chih-Ling Tsai

引用次数: 1