Determining the Number of Factors in Approximate Factor Models

In this paper we develop some econometric theory for factor models of large dimensions. The focus is the determination of the number of factors (r), which is an unresolved issue in the rapidly growing literature on multifactor models. We first establish the convergence rate for the factor estimates that will allow for consistent estimation of r. We then propose some panel criteria and show that the number of factors can be consistently estimated using the criteria. The theory is developed under the framework of large cross‐sections (N) and large time dimensions (T). No restriction is imposed on the relation between N and T. Simulations show that the proposed criteria have good finite sample properties in many configurations of the panel data encountered in practice.     

Asymptotic Comparison Between Constant-stress Testing and Step-stress Testing for Type-I Censored Data from Exponential Distribution

By running the life tests at higher stress levels than normal operating conditions, accelerated life testing quickly yields information on the lifetime distribution of a test unit. The lifetime at the design stress is then estimated through extrapolation using a regression model. In constant-stress testing, a unit is tested at a fixed stress level until failure or the termination time point of the test, while step-stress testing allows the experimenter to gradually increase the stress levels at some pre-fixed time points during the test. In this article, the optimal k-level constant-stress and step-stress accelerated life tests are compared for the exponential failure data under Type-I censoring. The objective is to quantify the advantage of using the step-stress testing relative to the constant-stress one. A log-linear relationship between the mean lifetime parameter and stress level is assumed and the cumulative exposure model holds for the effect of changing stress in step-stress testing. The optimal design point is then determined under C-optimality, D-optimality, and A-optimality criteria. The efficiency of step-stress testing compared to constant-stress testing is discussed in terms of the ratio of optimal objective functions based on the information matrix.     

Uniform Tail Asymptotics for the Sum of Two Correlated Classes with Stochastic Returns and Dependent Heavy Tails

Consider a continuous-time risk model with two correlated classes of insurance business and risky investments whose price processes are geometric Lévy processes. By assuming that the correlation comes from a common shock, and the claim sizes are heavy-tailed and pairwise quasi-asymptotically independent, we investigate the tail behavior of the sum of the stochastic present values of the two correlated classes, and a uniform asymptotic formula is obtained.     

A Survey of Campus Peer Counseling Activities

Abstract

The directors of counseling services at 200 colleges and universities were contacted by mail and asked to complete a survey regarding peer counseling activities on their campuses. One hundred fifty-six responses to this questionnaire were received; one hundred twenty-two indicated ongoing peer counseling activities in a wide variety of settings at their respective campuses. The most common client concerns confronted by peer counselors involved academic difficulties and relationships with friends and lovers. The survey identified a variety of peer counseling training programs, from one-weekend, intensive encounter-type experiences to full-year credit courses in counseling and therapy. Also examined were the funding resources available for peer counseling centers, which often proved quite marginal, and the amount of interaction between student counselors and professional mental health service staff members. Although the authors have been able to uncover a great many peer counseling programs on college campuses, there is a dearth of systematic research evaluating the effectiveness of the services provided by these centers or the appropriateness of various peer counselor training programs. Such work should be encouraged.     

Population planning in Asia in the 1970s

Analysis of data from various phases of a study of post-partum amenorrhoea in Bangladesh illustrated good aggregate consistency of response on menstrual status, but less individual consistency on duration of post-partum amenorrhoea. Using life table techniques, the median duration of amenorrhoea was calculated as 19.9 months for women with births between February and September 1974. There were substantial seasonal variations in duration, with the median decreasing from 21.5 months for women with February births to 16.9 months for those with September births. By contrast, the median duration of post-partum amenorrhoea varies by only two months for women in the lowest and highest quartiles of weight and weight for height. The seasonal pattern was similar for all weight groups.     

Quality and the 2010 Census

The U.S. Census Bureau has a long tradition of evaluating the results of its censuses. This paper presents evaluation results from the 2010 Census, comparing them to earlier results. The paper discusses net coverage at the national and state level, as well as by age, sex, race, and ethnic group. It discusses components of error, including estimated number missed and counted in error. It also presents data on whole-person and item imputation.     

Is brief daily body–mind–spirit practice desirable for staff who provide services for elderly people? Two pilot studies with care and professional workers

A symptoms-focused approach had only limited short-term effects in addressing burnout. A new trend is toward a positive approach in fostering well-being in the workplace. The current study piloted a daily body–mind–spirit practice programme which provided a 15-minute small-group meeting with staff who provide services for elderly people, towards the end of every workday for one month at two study sites. Repeated measures of burnout, daily spiritual experience (DSE) and engagement were taken at pre-intervention, post-intervention (the intervention lasted for one month) and one month after intervention. The two groups, home help workers and professional staff respectively, showed different patterns in burnout reduction and increase of DSE.     

Playing,Sitting Out,and Observing the Game: An Investigation of Faculty Members’ Perspectives on Political Behavior in Ethical Decision Making

Ethical dilemmas are inherently ambiguous, complex, and ill-defined. Additionally, these dilemmas involve multiple stakeholders. These characteristics may induce political behavior as a resolution tactic. Thus, the goal of the present effort was to investigate perspectives on politics among researchers in an ethical decision-making context. A qualitative analysis of interviews with university faculty members revealed that faculty members’ perspectives on political behavior in an ethical decision-making context fall into a number of categories, including positive, negative, and realistic views of political activity. The implications of these varying perspectives on ethical decision making are discussed.