A Stochastic Goal Program for Employee Scheduling*

Deterministic goal programs for employee scheduling decisions attempt to minimize expected operating costs by assigning the ideal number of employees to each feasible schedule. For each period in the planning horizon, managers must first determine the amount of labor that should be scheduled for duty. These requirements are often established with marginal analysis techniques, which use estimates for incremental labor costs and shortage expenses. Typically, each period in the planning horizon is evaluated as an independent epoch. An implicit assumption is that individual employees can be assigned to schedules with as little as a single period of work. If this assumption violates local work rules, the labor requirements parameters for the deterministic goal program may be suboptimal. As we show in this research, this well-known limitation can lead to costly staffing and scheduling errors. We propose an employee scheduling model that overcomes this limitation by integrating the labor requirements and scheduling decisions. Instead of a single, externally determined staffing goal for each period, the model uses a probability distribution for the quantity of labor required. The model is free to choose an appropriate staffing level for each period, eliminating the need for a separate goal-setting procedure. In most cases this results in better, less costly decisions. In addition, the proposed model easily accommodates both linear and nonlinear under- and overstaffing penalties. We use simple examples to demonstrate many of these advantages and to illustrate the key techniques necessary to implement our model. We also assess its performance in a study of more than 1,700 simulated stochastic employee scheduling problems.     

Distributing Journals to the World

Abstract

In 2001, a number of initiatives began for distributing research journals to parts of the world where they are otherwise not accessible. This “Balance Point” reports on two publishers whose journals are now more broadly available in developing nations. HighWire Press offers both a free back issue archive and a developing countries initiative. Blackwell Publishing is working with a Russian consortium to make journals available to Russian universities and with nongovernmental organizations to provide free or nearly free access to biomedical journals in a number of developing nations. Serials Review 2002; 28:113–115.     

Female harassment after ending a relationship: A preliminary study

While dramatic instances of male aggression directed toward women, such as rape and wife battering, have been frequently studied, a more subtle form of male aggression—female harassment—has been investigated less often. In the present study, 50 women who had terminated relationships with males and then were harassed were interviewed. In general, the harassment lasted for about a year, and episodes which occurred on a daily basis consisted of calls, letters, visits to home or work, being followed, verbal threats, and physical aggression. For the most part, these aggressive actions were perceived as both threatening and disturbing. Findings indicated that assertive female strategies were not more effective in reducing harassment than more sex-role stereotyped passive and nonassertive responses to male aggression. In the second phase of this study a sample of college undergraduates was interviewed on the topic of harassment. Fifty-six percent of the women indicated that they had been harassed by men.My thanks to Lyn De Amicis and LaVome Robinson for their instructive and helpful comments.     

Psychometric analysis of the UK Health and Safety Executive's Management Standards work-related stress Indicator Tool

Abstract

Numerous tools have been developed that attempt to measure work-related stress and working conditions, but few practical instruments in the literature have been found to have a reliable psychometric factor structure. In the UK, the Health and Safety Executive (HSE) Management Standards (MS) Indicator Tool is increasingly used by organizations to monitor working conditions that can lead to stress. In Health and Safety Executive (2004), a factor analysis was conducted demonstrating the reliability of the scales. However, the authors acknowledged that direct reassessment of the same factor structure was impossible as the questionnaire was split into two separate modules for data collection. Furthermore, the tool is designed to enable comparisons between as well as within organizations to take place, yet reliability has only previously been tested at the individual level. The current study is the first to examine the factor structure of the HSE MS Indicator Tool using organizational-level data. Data collected from 39 UK organizations (N=26,382) was used to perform a first-order Confirmatory Factor Analysis (CFA) on the original 35-item seven-factor measurement scale. The results showed an acceptable fit to the data for the instrument. A second-order CFA was also performed to test if the Indicator Tool contains a higher order uni-dimensional measure of work-related stress. These findings also revealed an acceptable fit to the data, suggesting that it may be possible to derive a single measure of work-related stress. Normative data comprising tables of percentiles from the organizational data are provided to enable employers to compare their organizational averages against national benchmarks.     

Stochastic models of industrial buying behaviour

This paper presents one of the first attempts to develop stochastic models of industrial buying behaviour. The Beta-binomial model, used to model consumer purchase incidence, also works well for industrial consumers. Purchase size is shown to be lognormally distributed suggesting that something like a log random walk process may be operating. However it proved impossible to combine these two stochastic models analytically and a less rich model, the Markov reservoir, was shown to fit the data providing useful insights into the dynamics of industrial markets as well as suggesting areas for further research.     

The Effect of Severe Child Sexual Abuse and Disclosure on Mental Health during Adulthood

This study examined the relationship among severe child sexual abuse, disclosure, and mental health symptoms during adulthood. The sample consisted of 172 adults who were sexually abused in childhood. The multivariate model showed that respondents in their 30s and 40s who were abused by more than one abuser, who were injured by their abusers, who were abused by a biological relative, who told someone about the abuse when it occurred, and who did not discuss their abuse in depth within one year of the abuse had a greater number of mental health symptoms. Abuse severity and disclosure history should be assessed by professionals to identify clients who are at higher risk of mental health symptoms and to focus therapy.