Strong Consistency of the Maximum Likelihood Estimator in Generalized Linear and Nonlinear Mixed-Effects Models

Generalized linear and nonlinear mixed-effects models are used extensively in biomedical, social, and agricultural sciences. The statistical analysis of these models is based on the asymptotic properties of the maximum likelihood estimator. However, it is usually assumed that the maximum likelihood estimator is consistent, without providing a proof. A rigorous proof of the consistency by verifying conditions from existing results can be very difficult due to the integrated likelihood. In this paper, we present some easily verifiable conditions for the strong consistency of the maximum likelihood estimator in generalized linear and nonlinear mixed-effects models. Based on this result, we prove that the maximum likelihood estimator is consistent for some frequently used models such as mixed-effects logistic regression models and growth curve models.     

On the optimal size of Social Security in the presence of a stock market

The paper develops a stylized overlapping generations economy with random production and a stock market. The impact of a Social Security system on production, asset markets, and consumer welfare is analyzed. It is shown that any reduction in the contribution rate fosters capital accumulation and increases asset prices, wages, and production output. Different welfare criteria are applied to determine the optimal size of Social Security. It is shown that there exists a unique contribution rate which is long-run optimal, socially optimal, and time-consistent in the sense that no generation has an incentive to change it.     

Accounting for the Accuracy of Beta Estimates in CAPM Tests on Assets with Time-varying Risks

This paper advocates two ways to make more efficient use of available information in reducing the bias of the risk premium estimate in two-pass tests of the CAPM. First, explicit modelling of the time-variability of betas can improve the accuracy of the beta forecasts. Second, the cross-sectional information available can be exploited more efficiently using individual stocks instead of portfolios provided that noisy beta predictions are given a smaller weight than more accurate ones. This paper proposes an adjustment of the cross-sectional regressions of excess returns against betas to give larger weights to more reliable beta forecasts. A significant positive relationship between returns and the beta forecast is obtained when the proposed approach is applied to data from the Helsinki Stock Exchange, while the traditional Fama–MacBeth approach as such finds no relationship at all.     

On the role of labor supply for the optimal size of Social Security

The paper studies the welfare effects of a Social Security system in a stylized overlapping generations economy with random production and capital accumulation. Different welfare concepts including long run optimality, social optimality, and time consistency are employed to determine the optimal size of the system. When labor supply is exogenous, a unique contribution level can be identified which is optimal according to all three concepts. When labor supply is endogenous, however, this result generically fails to hold and the long-run optimal solution is only constrained socially optimal while the time-consistent policy may even lead to an inefficient equilibrium.     

A strategic website evaluation of online travel agencies

Online travel Web sites have been the most frequently visited online information facilities by travelers. To evaluate the effectiveness of a travel Web site, the Web site manager should regularly check whether or not it is fulfilling the objectives that were established for it. This research uses a strategic Web site evaluation framework to introduce a five-stage process for examining the consistency of Web site’s presence and its intended strategies. Two leading online travel agencies with different business strategies are selected to demonstrate methods of implementing a strategic evaluation framework and to compare the evaluation results. A hierarchical evaluation structure is introduced to explicitly delineate the two Web sites’ different strategy intentions and related evaluation criteria. Results show that an individual Web site’s strategy-inconsistent criteria can be easily identified through a gap analysis and criteria performance matrix. A strategy-inconsistent dimension can be discovered through a radar chart analysis of the 4PsC (Product, Promotion, Price, Place, and Customer Relationship) dimensions and a transaction phases analysis.     

基于组合评价的区域可持续发展能力实证研究——以福建省为例

区域可持续发展是一个复杂的耦合系统。从经济、社会、科技、文化、环境、生态、人口、文化八个方面建立全面、系统的可持续发展系统的评价指标体系，并采用组合评价方法集的方法进行评价，克服了单一评价方法的非一致性的缺点。对福建省九个地市2011年的统计数据进行处理，将其可持续发展能力进行排序，并对评价结果进行分析，提出相关政策建议。     

Random scheduling with deadlines under dichotomous preferences

A group of individuals share a deterministic server which is capable of serving one job per unit of time. Every individual has a job and a cut off time slot (deadline) where service beyond this slot is as worthless as not getting any service at all. Individuals are indifferent between slots which are not beyond their deadlines (compatible slots). A schedule (possibly random) assigns the set of slots to individuals by respecting their deadlines. We only consider the class of problems where for every set of relevant slots (compatible with at least one individual) there are at least as many individuals who have a compatible slot in that set: we ignore the case of underdemand. For this class, we characterize the random scheduling rule which attaches uniform probability to every efficient deterministic schedule (efficient uniform rule) by Pareto efficiency, equal treatment of equals, and probabilistic consistency (Chambers, 2004). We also show that a weaker version of the probabilistic consistency axiom is enough to achieve our result. Finally we show that efficient uniform rule is strategyproof.     

Dynamic quasi concave performance measures

We define Conditional quasi concave Performance Measures (CPMs), on random variables bounded from below, to accommodate for additional information. Our notion encompasses a wide variety of cases, from conditional expected utility and certainty equivalent to conditional acceptability indexes. We provide the characterization of a CPM in terms of an induced family of conditional convex risk measures. In the case of indexes these risk measures are coherent. Then, Dynamic Performance Measures (DPMs) are introduced and the problem of time consistency is addressed. The definition of time consistency chosen here ensures that the positions which are considered good tomorrow are already considered good today. Finally, we investigate the relation between time consistency for a DPM and weak acceptance consistency for the induced families of risk measures.     

Asymptotic properties of estimators for the volume fractions of jointly stationary random sets

In the present paper, we show how a consistent estimator can be derived for the asymptotic covariance matrix of stationary 0–1-valued vector fields in R ^d , whose supports are jointly stationary random closed sets. As an example, which is of particular interest for statistical applications, we consider jointly stationary random closed sets associated with the Boolean model in R ^d such that the components indicate the frequency of coverage by the single grains of the Boolean model. For this model, a representation formula for the entries of the covariance matrix is obtained.     

Response Effects in Surveys on Children and Adolescents: The Effect of Number of Response Options,Negative Wording,and Neutral Mid-Point

Social researchers increasingly survey children and young adolescents.They are convinced that information about perspectives, attitudes, and behaviors of childrenshould be collected from the children themselves. Methodological expertise on surveying childrenis still scarce, and researchers rely on ad-hoc knowledge from fields such as child psychiatry and educationaltesting, or on methodological knowledge on surveying adults. Regarding adults, empirical evidenceshows that respondent characteristics (cognitive abilities) as well asquestion characteristics (question difficulty) affect response quality.This study reports on a methodological survey experiment on theeffect of negatively formulated questions, the number of response options and offeringa neutral midpoint as response option question characteristics on the reliability of theresponses, using children and young adolescents as respondents.The study shows no effects of negatively formulated questions onthe reliability measures, although children respond consistently differently on negativelyformulated questions than on positively formulated questions. Taking all results on the effectsof number of response options and offering a neutral midpoints on the different reliabilitymeasures into consideration; it would appear that offering about four responseoptions is optimal with children as respondents.