Estimation of the need for child care in Canada

Finding adequate child care is a serious problem for many Canadian parents. The purpose of this case study is to estimate the need for child care in Canada, including ihc portion of this need that may be hidden. We utilize the Family History Survey conducted by Statistics Canada (1984) to explore patterns of both met and unmet child-care needs, based, in the latter case, on varying assumptions about the degree of parents' desire for child care.     

One-Class Classification-Based Control Charts for Monitoring Autocorrelated Multivariate Processes

In recent years, statistical process control (SPC) of multivariate and autocorrelated processes has received a great deal of attention. Modern manufacturing/service systems with more advanced technology and higher production rates can generate complex processes in which consecutive observations are dependent and each variable is correlated. These processes obviously violate the assumption of the independence of each observation that underlies traditional SPC and thus deteriorate the performance of its traditional tools. The popular way to address this issue is to monitor the residuals—the difference between the actual value and the fitted value—with the traditional SPC approach. However, this residuals-based approach requires two steps: (1) finding the residuals; and (2) monitoring the process. Also, an accurate prediction model is necessary to obtain the uncorrelated residuals. Furthermore, these residuals are not the original values of the observations and consequently may have lost some useful information about the targeted process. The main purpose of this article is to examine the feasibility of using one-class classification-based control charts to handle multivariate and autocorrelated processes. The article uses simulated data to present an analysis and comparison of one-class classification-based control charts and the traditional Hotelling's T ² chart.     

Vaccine clinical trials with dynamic borrowing of historical controls: Two retrospective studies

Traditional vaccine efficacy trials usually use fixed designs with fairly large sample sizes. Recruiting a large number of subjects requires longer time and higher costs. Furthermore, vaccine developers are more than ever facing the need to accelerate vaccine development to fulfill the public's medical needs. A possible approach to accelerate development is to use the method of dynamic borrowing of historical controls in clinical trials. In this paper, we evaluate the feasibility and the performance of this approach in vaccine development by retrospectively analyzing two real vaccine studies: a relatively small immunological trial (typical early phase study) and a large vaccine efficacy trial (typical Phase 3 study) assessing prophylactic human papillomavirus vaccine. Results are promising, particularly for early development immunological studies, where the adaptive design is feasible, and control of type I error is less relevant.     

Reduced rank proportional hazards model for competing risks: An application to a breast cancer trial

In many cancer trials patients are at risk of recurrence and death after the appearance and the successful treatment of the first diagnosed tumour. In this situation competing risks models that model several competing causes of therapy or surgery failure are a natural framework to describe the evolution of the disease.Typically, regression models for competing risks outcomes are based on proportional hazards model for each of the cause-specific hazard rates. An immediate practical problem is then how to deal with the abundance of regression parameters. The aim of reduced rank proportional hazards models is to reduce the number of parameters that need to be estimated while at the same time keeping the distinction between different transitions. They have the advantage of describing the competing risks model in fewer parameters, cope with transitions where few events are present and facilitate the interpretation of these estimates.We shall illustrate the use of this technique on 2795 patients from a breast cancer trial (EORTC 10854).     

养老保险个人账户的动态平衡研究

针对目前中国养老保险个人账户难以做实的现状,本文首先推算出未来各年龄别职工人数和工资的动态变化过程,然后在精算模型的基础上调整了部分公式,试图更好地还原实际情况,并以此测算出个人账户在未来每一期的结余情况。结果显示,未来十余年现有制度仍可以持续运行,虽然没有出现收不抵支的局面,但个人账户的做实比例仅在60%-75%,缺口较大,需要寻求大量额外资金注入来辅助其完成实账化。     

Approximate and exact distributions of rank tests for balanced incomplete block designs

Judges rank k out of t objects according to m replic ations of abasic balanced incomplete block design with bblocks. In Alvo and Cabilio(1991),it is shown that the Durbin test, which is the usual test in this situation, can be written in terms of Spearman correlations between the blocks, and using a Kendall correlation, they generated a new statistic for this situation.This Kendall tau based statistic has a richer support than the Durbin statistic, and is at least as efficient.In the present paper,exact and simulation based tables are generated for both statistics, and various approximations to these null distributions are considered and compared.     

Estimating standard error of intra-class correlation coefficients up to three level unbalanced nested clinical trials

ABSTRACT

Very often researchers plan a balanced design for cluster randomization clinical trials in conducting medical research, but unavoidable circumstances lead to unbalanced data. By adopting three or more levels of nested designs, they usually ignore the higher level of nesting and consider only two levels, this situation leads to underestimation of variance at higher levels. While calculating the sample size for three-level nested designs, in order to achieve desired power, intra-class correlation coefficients (ICCs) at individual level as well as higher levels need to be considered and must be provided along with respective standard errors. In the present paper, the standard errors of analysis of variance (ANOVA) estimates of ICCs for three-level unbalanced nested design are derived. To conquer the strong appeal of distributional assumptions, balanced design, equality of variances between clusters and large sample, general expressions for standard errors of ICCs which can be deployed in unbalanced cluster randomization trials are postulated. The expressions are evaluated on real data as well as highly unbalanced simulated data.     

Valid estimates for repeated randomized response methods

Surveys with sensitive characteristics (e.g. cheating in exams, fiscal evasion, social fraud, insurance fraud, discrimination, political views, financial situation) need special concepts, because normal direct questioning causes answer refusal and lies. One well-established concept is the randomized response (RR) approach. RRs protect the interviewees' privacy and facilitate their cooperation. Based on the RRs of many persons, inference is possible. A recently published article suggests two repeated RR methods. That is, each interviewee must give more than one answer. Repeated RRs are a good idea to improve the estimation efficiency of RR techniques. However, this recently published article contains serious mistakes and derives invalid estimates. For this reason, we correct these mistakes and develop valid estimates in the first part of our article. Subsequently, in the second part, we present generalized considerations that cover many more repeated RR schemes.     

How not to fund hospital and community health services in England

Summary.  The paper focuses on the hospital and community health service component of the current formula for the target allocation of annual 'weighted capitation' funding of England's 304 primary care trusts—a formula that responds to political pressure to tackle continuing health inequalities. The history of allocation formulae for the National Health Service is briefly reviewed, before exposing the composition and provenance of the hospital and community health service component. Under the heading 'Logical and statistical deficiencies' we consider various frameworks, model misspecification, allowance for age, ins and outs of supply, unmet need and wrong signs, and replicability and robustness—questions that are relevant to trust in the current formula based on the regression of age-standardized current utilization on a multiplicity of socioeconomic variables. We conclude that it might be better to put future resources into developing direct, rather than proxy, measurement of health needs.     

抗肿瘤药物贝叶斯Ⅰ期临床试验设计方法比较研究

Ⅰ期临床试验的主要目的是探索药物毒性最大耐受剂量MTD,而MTD估计的准确与否将影响之后的Ⅱ期和Ⅲ期临床试验研究的结果.抗肿瘤药物Ⅰ期试验的特点是直接对病人进行试验,且样本量较小,这对构造估计精确度高并具有安全性保障要求的统计设计方法提出了挑战.回顾三种常用的Ⅰ期试验设计方法有:3+3设计、CRM设计和mTPI设计.3+3设计是应用较为广泛的传统方法,后两者是当前常用的贝叶斯自适应试验设计方法.通过大量模拟研究对三种方法从最优分配、安全性和估计MTD精确性三方面给以全面考察,并结合中国实际得出mTPI设计是比较适合推荐的Ⅰ期临床试验设计方法的结论.     

Smoothing for small samples with model misspecification: nonparametric and semiparametric concerns

Our goal is to find a regression technique that can be used in a small-sample situation with possible model misspecification. The development of a new bandwidth selector allows nonparametric regression (in conjunction with least squares) to be used in this small-sample problem, where nonparametric procedures have previously proven to be inadequate. Considered here are two new semiparametric (model-robust) regression techniques that combine parametric and nonparametric techniques when there is partial information present about the underlying model. A general overview is given of how typical concerns for bandwidth selection in nonparametric regression extend to the model-robust procedures. A new penalized PRESS criterion (with a graphical selection strategy for applications) is developed that overcomes these concerns and is able to maintain the beneficial mean squared error properties of the new model-robust methods. It is shown that this new selector outperforms standard and recently improved bandwidth selectors. Comparisons of the selectors are made via numerous generated data examples and a small simulation study.     

中国国民财富总量、结构及其演进模式研究——基于“自上而下-自下而上”测度范式

“财富-福利等式”表明国民财富与社会福利具有理论等价关系,是评估发展可持续性的最优指示器。我国国民财富研究相对滞后,总量测度与结构分析都亟待深化。本文基于“自上而下-自下而上”范式,依据国情优化关键参数的设定,改进了我国国民财富与分类资本估算,并剖析了省际国民财富结构以识别其演进模式。研究发现:由于资源禀赋与发展阶段有别,省际国民财富结构差异显著;随着经济发展水平提升,国民财富结构先由自然资本主导转向物质资本与人力资本共同主导,进而转变为人力资本主导,最终迈入社会资本主导。各地区应结合自身禀赋与发展阶段做好“投资组合管理”,以此来提升国民财富并优化其结构从而改善经济发展的持续性。     

Rank‐based estimate of four‐parameter logistic model

During drug development, the calculation of inhibitory concentration that results in a response of 50% (IC₅₀) is performed thousands of times every day. The nonlinear model most often used to perform this calculation is a four‐parameter logistic, suitably parameterized to estimate the IC₅₀ directly. When performing these calculations in a high‐throughput mode, each and every curve cannot be studied in detail, and outliers in the responses are a common problem. A robust estimation procedure to perform this calculation is desirable. In this paper, a rank‐based estimate of the four‐parameter logistic model that is analogous to least squares is proposed. The rank‐based estimate is based on the Wilcoxon norm. The robust procedure is illustrated with several examples from the pharmaceutical industry. When no outliers are present in the data, the robust estimate of IC₅₀ is comparable with the least squares estimate, and when outliers are present in the data, the robust estimate is more accurate. A robust goodness‐of‐fit test is also proposed. To investigate the impact of outliers on the traditional and robust estimates, a small simulation study was conducted. Copyright © 2012 John Wiley & Sons, Ltd.     

Modelling and research on manufacturer’s capacity of remanufacturing and recycling in closed-loop supply chain

This paper introduces and analyses the present situation of the electronic waste recycling at home and abroad. Involving manufacturers in the recycling process of supply chain as the dominant party and establishing the closed-loop supply chain system structure model of the waste electronic products recycling, the effects of remanufacturing capacity and recycling coefficient on the closed-loop supply chain recycling network are analysed by using system dynamics method. The simulation results show that, compared with the traditional supply chain, the total revenue of the supply chain under the recycling mode dominated by manufacturers has improved, that the increase of the remanufacturing capacity has promoted the growth of the electronic product's sales rate, which reaches a equilibrium when remanufacturing capacity is set as 0.36, and that the recycling efficiency of e-waste has improved significantly as the e-waste recycling coefficient constantly increased.     

Developing a Freely Accessible/Open Access Resource Management Policy at Duke University Libraries: A Case Study

Abstract

Freely accessible and open access resources present unique challenges for librarians working with electronic resources. Due to the fact that many of these resources lack high-quality metadata or the technical support provided by traditional publishers, making them discoverable and maintaining access over time can be tricky. Creating a policy allows for a systematic approach to the management of freely accessible/open access (OA) resources, alleviating problems surrounding lack of staff time or expertise. Many of these resources are already important parts of collections and will only continue to grow in importance. Freely accessible/OA resources allow for a more diverse representation of content, both by subject and format type, and allow a wider array of authors to have their work appear in library collections. This case study will provide a review of freely accessible/OA policies in other libraries, describe why these resources are important to add to our collections, discuss challenges libraries face with managing these resources, and explain how Duke University Libraries is addressing some of these challenges through the development of a policy.     

A TWO-STAGE UNRELATED RANDOMISED RESPONSE PROCEDURE

In a sample survey, questions requiring personal or controversial assertions often give rise to resistance. A randomised response procedure can be used to help the researcher gather accurate data in this case. This paper describes a new two-stage unrelated randomised response procedure that combines the use of two randomisation devices (Mangat & Singh, 1990) and an unrelated question (Horwitz et al. 1967). It examines the situation where the respondents are not completely truthful in their answers. The efficiency of this new method is compared with the original one-stage procedure proposed by Horwitz et al. (1967), and guidelines for choosing the values of different parameters for the procedures are provided. Results from an empirical study which examines the efficiency and feasibility of the proposed method are given.     

Rapid penalized likelihood-based outlier detection via heteroskedasticity test

Outlier detection is fundamental to statistical modelling. When there are multiple outliers, many traditional approaches in use are stepwise detection procedures, which can be computationally expensive and ignore stochastic error in the outlier detection process. Outlier detection can be performed by a heteroskedasticity test. In this article, a rapid outlier detection method via multiple heteroskedasticity test based on penalized likelihood approaches is proposed to handle these kinds of problems. The proposed method detects the heteroskedasticity of all data only by one step and estimate coefficients simultaneously. The proposed approach is distinguished from others in that a rapid modelling approach uses a weighted least squares formulation coupled with nonconvex sparsity-including penalization. Furthermore, the proposed approach does not need to construct test statistics and calculate their distributions. A new algorithm is proposed for optimizing penalized likelihood functions. Favourable theoretical properties of the proposed approach are obtained. Our simulation studies and real data analysis show that the newly proposed methods compare favourably with other traditional outlier detection techniques.     

Modelling the travel time of transit vehicles in real‐time through a GTFS‐based road network using GPS vehicle locations

Predicting the arrival time of a transit vehicle involves not only knowledge of its current position and schedule adherence, but also traffic conditions along the remainder of the route. Road networks are dynamic and can quickly change from free‐flowing to highly congested, which impacts the arrival time of transit vehicles, particularly buses which often share the road with other vehicles, so reliable predictions need to account for real‐time and future traffic conditions. The first step in this process is to construct a framework with which road state (traffic conditions) can be estimated using real‐time transit vehicle position data. Our proposed framework implements a vehicle model using a particle filter to estimate road travel times, which are used in a second model to estimate real‐time traffic conditions. Although development and testing took place in Auckland, New Zealand, we generalised each component to make the framework compatible with other public transport systems around the world. We demonstrate the real‐time feasibility and performance of our approach in real‐time, where a combination of R and C++ was used to obtain the necessary performance results. Future work will use these estimated traffic conditions in combination with historical data to obtain reliable arrival time predictions of transit vehicles.     

New critical values for the generalized t and generalized rank-sum procedures

Student's t test as well as Wilcoxon's rank-sum test may be inefficient in situations where treatments bring about changes in both location and scale. In order to rectify this situation, O'Brien (1988, Journal of the American Statistical Association 83, 52-61) has proposed two new statistics, the generalized t and generalized rank-sum procedures, which may be much more powerful than their traditional counterparts in such situations. Recently, however, Blair and Morel (1991, Statistics in Medicine in press) have shown that referencing these new statistics to standard F tables as recommended by O'Brien results in inflations of Type I errors. This paper provides tables of critical values which do not produce such inflations. Use of these new critical values results in Type I error rates near nominal levels for the generalized t statistic and slightly conservative rates for the generalized rank-sum test. In addition to the critical values, some new power results are given for the generalized tests.