Coping with Time‐Varying Demand When Setting Staffing Requirements for a Service System

We review queueing‐theory methods for setting staffing requirements in service systems where customer demand varies in a predictable pattern over the day. Analyzing these systems is not straightforward, because standard queueing theory focuses on the long‐run steady‐state behavior of stationary models. We show how to adapt stationary queueing models for use in nonstationary environments so that time‐dependent performance is captured and staffing requirements can be set. Relatively little modification of straightforward stationary analysis applies in systems where service times are short and the targeted quality of service is high. When service times are moderate and the targeted quality of service is still high, time‐lag refinements can improve traditional stationary independent period‐by‐period and peak‐hour approximations. Time‐varying infinite‐server models help develop refinements, because closed‐form expressions exist for their time‐dependent behavior. More difficult cases with very long service times and other complicated features, such as end‐of‐day effects, can often be treated by a modified‐offered‐load approximation, which is based on an associated infinite‐server model. Numerical algorithms and deterministic fluid models are useful when the system is overloaded for an extensive period of time. Our discussion focuses on telephone call centers, but applications to police patrol, banking, and hospital emergency rooms are also mentioned.     

Faces Behind the Figures: Interviews with Children Excluded from Primary School

This article presents a viewpoint on school exclusion from 22 primary-age children excluded from 20 different schools in two English local education authorities, (a county council and an inner London borough) during the 1993–94 academic year. Some of the methodological and ethical issues about researching children are outlined and considered. The approach and methods used in the research are explained. Interviews with children showed exclusion to be a significant but negative event for them, yet they were optimistic about a return to school. Children showed an awareness of what was considered to be appropriate or inappropriate behaviour in their school. They frequently referred to incidents of physical aggression as the reason for their exclusion. It is concluded that this awareness of appropriate behaviour as well as their optimism must be recognised and harnessed when young children are reintegrated into school following a period of exclusion.     

Safety First: A Model of Care for Working Systemically With High Risk Young People and Their Families in an Acute CAMHS Service

The following article outlines the Safety First Model for working with high‐risk young people in crisis. This hierarchical model prioritises emotional and physical safety by using multi‐systemic and family‐based interventions. A typical case example is used to illustrate the model and the structures and strategies employed at each level. The intervention model empowers families, facilitates their connections with other providers, and minimises the need for hospital admissions. The model also promotes collaborative and systemic practice in a child and adolescent mental health service.     

THE MEANING OF RACE TO EMPLOYERS:

The unemployment problems of blacks in the United States have been the subject of considerable research in the social sciences since the 1980s. One way of studying the barriers to employment faced by blacks has been to interview employers, face to face, and directly ask them about their racial attitudes. These studies have concluded that a majority of employers believe that blacks, compared with other racial and ethnic groups, are uncooperative, unreliable, and lack sufficient skills for entry-level employment. The present study critically reexamines employer racial attitudes toward blacks and other groups through a case study of employer hiring in the electronics industry in Los Angeles. Using a different set of interview questions, employers reported (1) that blacks are reluctant to accept unskilled jobs due to a higher reservation wage, not because they lacked skills or a work ethic, (2) that employer racial attitudes varied by level of occupational skill, and (3) that affirmative action regulations modified the hiring process such that employers were less likely to rely on negative racial stereotypes in their hiring and more likely to rely on objective criteria when screening job seekers. I conclude by suggesting that employer racial attitudes are dynamic and, in large measure, shaped by institutional relationships within the workplace.     

Survival estimation and the effects of dependency among animals

Survival models assume that fates of individuals are independent, yet the robustness of this assumption has been poorly quantified. We examine how empirically derived estimates of the variance of survival rates are affected by dependency in survival probability among individuals. We used Monte Carlo simulations to generate known amounts of dependency among pairs of individuals and analyzed these data with Kaplan-Meier and Cormack-Jolly-Seber models. Dependency significantly increased these empirical variances as compared to theoretically derived estimates of variance from the same populations. Using resighting data from 168 pairs of black brant ( Branta bernicla nigricans ), we used a resampling procedure and program RELEASE to estimate empirical and mean theoretical variances. We estimated that the relationship between paired individuals caused the empirical variance of the survival rate to be 155% larger than the empirical variance for unpaired individuals. Monte Carlo simulations and use of this resampling strategy can provide investigators with information on how robust their data are to this common assumption of independent survival probabilities.     

The Role of Leader Influence Tactics and Safety Climate in Engaging Employees'' Safety Participation

This study examines the effect of leader influence tactics on employee safety participation in a U.K.-based manufacturing organization, examining the role of safety climate as a mediator. Structural equation modeling showed that leader influence tactics associated with a transformational leadership style had significant relationships with safety participation that were partially mediated by the safety climate (consultation) or fully mediated by the safety climate (inspirational appeals). In addition, leader influence tactics associated with a transactional leadership style had significant relationships with safety participation: rational persuasion (partially mediated by safety climate) and coalition tactics (direct effect). Thus, leaders may encourage safety participation using a combination of influence tactics, based on rational arguments, involvement in decision making, and generating enthusiasm for safety. The influence of building trust in managers is discussed as an underlying mechanism in this relationship. Practical implications are highlighted, including the design of leadership development programs, which may be particularly suited to high-reliability organizations.