Prioritizing and Monitoring Concurrent Project Work: Effects on Switching Behavior

Project switching occurs when a multi‐project worker shifts his/her attention from one project to another before completing the first project. In this study, we study the effects of two areas of management policy on project switching behavior, project prioritization, and work monitoring. We conduct a controlled experiment to evaluate direct and combined effects of prioritization, scheduled progress checks, and managerial progress checks on project switching behavior in a distributed, multi‐project work environment. We use computerized tasks constituting multiple projects as a means of efficiently simulating a project work setting. Working professionals served as subjects for the experiment, thereby enabling us to control for experience and other individual differences that may vary across workers in real‐world projects. We find that clarifying priorities has little overall effect on the prevalence of switching in our multi‐project setting, while the presence of managerial progress checks has significant and distinct impacts, driving up switch tendencies. Interestingly, various attributes of the timing of these monitoring events also significantly impact the likelihood that workers will switch in response to these event triggers. We discuss the implications of these findings for managerial practice and for future research.     

Designing Risk Communications: Completing and Correcting Mental Models of Hazardous Processes, Part I

Many risk communications are intended to help the lay public make complex decisions about risk. To guide risk communicators with this objective, a mental models approach to the design and characterization of risk communications is proposed. Building on text comprehension and mental models research, this approach offers an integrated set of methods to help the risk communication designer choose and analyze risk communication content, structure, and organization. An applied example shows that two radon brochures designed with this approach present roughly the same expert facts as a radon brochure widely distributed by the U.S. EPA but meet higher standards on other content, structure, and organization criteria.     

A social ecology approach and applications of urban ecosystem and landscape analyses: a case study of Baltimore,Maryland

The early interactions between plant, animal, and human ecology in the 1920s in the United States provide an initial basis for understanding and directing an integrated ecosystem approach to the study of sociocultural and biophysical patterns and processes of present day cities. However, whereas the human ecology approach of the 1920s and 30s was interested in metaphorical similarities with plant and animal ecologists, we propose a more integrated approach to human ecosystem observation and analysis. A critical feature to an integrated, urban ecosystem approach is the ability of researchers to address the spatial heterogeneity of urban ecosystems; i.e. the development and dynamics of spatial heterogeneity and the influences of spatial patterns on cycles and fluxes of critical resources (e.g. energy, materials, nutrients, genetic and nongenetic information, population, labor, and capital). An important question in this context is how differential access to and control over critical resources affect the structure and function of urban ecosystems.To address this heterogeneity, we illustrate a human ecosystem and landscape approach and how the concept of social differentiation can be applied spatially at different scales with a case study from our research in Baltimore, Maryland. Further, we identify different methods, tools, and techniques that can be used for an integrated, urban ecosystem approach.     

Generational equity and measurement bias: Who is really poor?

One core contention of the generational equity argument is that elderly people are financially well-off. To support this argument, generational equity proponents compare poverty rates of elderly people to those of children in the United States demonstrating that elderly people enjoy a privileged position in terms of financial well-being as compared to other age groups. I argue that the measurement of poverty upon which this argument is based is grounded in faulty logic and incorrect assumptions. Therefore, the basis of this generational equity argument is invalid. I conclude that using poverty rates creates the impression of a conflict between children and elderly people drawing attention away from the continuing problem of discrimination against women and minorities.     

DENSITY FUNCTION APPROXIMATION WITH PARTICULAR REFERENCE TO THE DISTRIBUTION OF OVERLAP OF CIRCLES

Given that two circles overlap, the area in common is a function of the distance between their centres. This paper adopts a suitable random distribution for the intercentre distance and then derives the distribution of the area of overlap. An approximation is sought for the density function using a criterion which enables bounds to be placed on the difference between the moments of the density function and those of the approximation. This is an approach of general applicability. The importance of matching the end-point behaviour of the density and the approximation is stressed. It is shown that the distribution of the area of overlap may be well approximated by a mixture of beta distributions in which the parameters change smoothly with the ratio of radii.     

Identifying influential observations in hierarchical cluster analysis

In a cluster analysis of a multivariate data set, it may happen that one or two observations have a disproportionately large effect on the analysis, in the sense that their removal causes a dramatic change to the results. It is important to be able to identify such influential observations, and the present paper addresses this problem. To do so, we must first quantify the effect of a single observation. Various definitions are discussed, and criteria for identifying influential observations are investigated; the minimum spanning tree and the number of neighbours of each observation are considered. The investigation concentrates on single-link cluster analysis, although complete-link analysis is also briefly discussed. Patterns emerge in both real and simulated data, which suggest ways of predicting observations with no effect and those with the greatest effect. It is not necessary to recalculate the results with each observation omitted—an economy of presentation as well as labour.     

Infants' Listening Preferences: Baby Talk or Happy Talk?

The most robust finding on infants' listening preferences has been widely characterized as a preference for baby talk (BT) over adult‐directed speech (ADS). Although prosodic modifications characteristic of BT also convey positive affect, differences in affect across BT and ADS speech registers have not been controlled in previous studies. This set of experiments sought to elucidate the basis for 6‐month‐olds' listening preference by independently manipulating affect and speech register. When affect was held constant, no preference for any speech register was observed. Moreover, when ADS stimuli presented more positive affect than BT stimuli, infants' preferences followed the positive affect. Higher and more variable pitch was neither necessary nor sufficient for determining infants' preferences, although pitch characteristics may modulate affect‐based preferences. The BT preference is thus attributable to a more general preference for speech that imparts relatively positive affect, a preference perhaps ascribable to a preexisting general‐purpose mechanism opportunistically exploited by language.     

What Do We Know About Making Risk Comparisons?

The risks of unfamiliar technologies are often evaluated by comparing them with the risks of more familiar ones. Such risk comparisons have been criticized for neglecting critical dimensions of risky decisions. In a guide written for the Chemical Manufacturers Association, Covello et al. (¹) have summarized these critiques and developed a taxonomy that characterizes possible risk comparisons in terms of their acceptability (or objectionableness). We asked four diverse groups of subjects to judge the acceptability of 14 statements produced by Covello et al. as examples of their categories. We found no correlation between the judgments of acceptability produced by our subjects and those predicted by Covello et al. .