A graphical method for comparing trends in series of events

This paper describes a new graphical method for comparing trends in two or more series of events. The method is applicable,e.g., to observations such as the successive times to failure of two or more devices and the arrival times on succeeding days at a service facility. The graphs provide information about the rela-tive trend and can be used to order several series with respect to rates of occurrence of events. The series are assumed independent of one another and are assumed to follow nonhomogeneous Poisson processes with mean functions and rate functions unspeci-fied.     

An Alternative Approach to Dietary Exposure Assessment

The method of dietary exposure assessment currently used by the Environmental Protection Agency (EPA), the Dietary Residue Evaluation System (DRES), combines a consumption distribution derived from the United States Department of Agriculture (USDA) 1977-1978 Nationwide Food Consumption Survey (NFCS) with a single estimate of residue level. The National Academy of Sciences'¹' recommended that EPA incorporate both the distribution of residues and the distribution of consumption into their exposure assessment methodology and proposed using a Monte Carlo approach. This paper presents an alternative method, the Joint Distributional Analysis (JDA), that combines the consumption and residue distributions, without relying on random sampling or fitting theoretical distributions like the Monte Carlo method. This method permits simultaneous analysis of the entire diet, including assessing exposure from residues in different foods.     

The Primary Risk

In the Tavistock tradition, we understand anorganization by first identifying its primary task. Weask, what is this organization set up to do, how is itorganized to accomplish this objective, and what unconscious dynamics limit or distort itsmembers' ability to do their work? This approach whilepowerful, does not help us understand organizations thatlive at strategic junctures in their life cycles. In these situations, the task is to choose atask. We need a conceptual framework to help usunderstand the psychodynamics of organizing and decidingin these situations. The following article develops the concept of the “primary risk”to explain how organizations behave in these situations.It links the primary risk to the psychoanalytic idea ofambivalence and the gestalt idea of the figure/ground relationship. It draws on case material toilluminate its concepts.     

Characterization of woodchuck burrows within seven sensitive areas at Antietam National Battlefield,Maryland

The goal of a two-year study of the woodchuck (Marmota monax) on Antietam National Battlefield (ANTI) in Maryland was to reduce continuing damage to the Park's unique cultural and historical resources caused by woodchuck burrowing and scent-marking behavior. Park managers were concerned with increased maintenance costs, loss of biological and historic resources, and visitor safety as a result of the high density woodchuck population. Data were collected on all burrow systems found within seven sensitive areas, defined as historical farmsteads and high visitor usage areas, within ANTI. Burrow activity status (active, inactive), number of entrances, presence of secure objects, distances to roads and walkways, and damage ratings were recorded for each system. Chewing and burrowing damage was assessed on its potential for the undermining of monuments, building foundations, rock walls and fences and its visibility to park visitors.Burrow systems (n = 115) were found at all sensitive area sites (range = 3–28) and burrows were significantly associated with secure objects (n = 81 with, n = 34 without; 2 = 19.38, P < .01). Cultural or historical objects had burrows associated with them more often than natural landscape features including rocks, trees or stumps (n = 62 cultural; n = 19 natural; 2 = 28.4, P < .01). The average distances of burrows to pedestrian traffic was 30.4 m across all sensitive areas. Chewing damage was found at six sensitive areas distributed nearly equally among woody vegetation, fences and buildings. Undermining of walls and buildings was more common than undermining of fences and monuments. Woodchuck burrowing damage was visible to the public at 33 (29%) of the burrow systems and the average damage rating was highest at the National Cemetery (1.8) and lowest at Burnside Bridge 1.1 (scale of one to three). The average damage rating for all sensitive areas was 1.4.Woodchucks may instinctively select secure objects for protection from predators. The animals' significant association with burrows in the sensitive areas makes secure objects an important contributing component of an area's suitability. An increase in maintenance and human activity combined with exclosure of woodchucks may reduce an area's suitability for woodchucks. Continued inventory and monitoring of areas of concern will be recommended as part of a pro-active management approach emphasizing habitat modification and suitability reduction based on our scientific findings.     

Community reintegration for people with psychiatric disabilities: challenging systemic barriers to service provision and public policy through participatory action research

People with psychiatric disabilities represent a growing group within the population of nursing home residents in the USA. Despite a preference for living in community‐based settings, the availability of supportive services for community living is hindered by barriers at both the service provision and public policy levels. Therefore, understanding and responding to the community living and participation needs of people with psychiatric disabilities is a highly relevant area for action research. This paper discusses a participatory action research endeavor carried out in collaboration with key personnel at Centers for Independent Living who work to provide community reintegration services for individuals with psychiatric disabilities. The events of this 15 month partnership are extensively described, analyzed and discussed. Findings reflect the critical need for communication, dialogue and action to support people with psychiatric disabilities in the community.     

From the suburbs to the house: The metropolitan–rural population and the success of women candidates

We analyze the voting behavior of metropolitan and rural residents in relation to women's legislative representation. Examining election data on the U.S. House and all lower state houses, we find that the greater the metropolitan population in a legislative district, the more likely it is to be represented by a woman. We extrapolate from these findings that the modern increase in women's representation can be attributed in part to the rural-to-suburban shift in population and legislative seats.     

REVISITING ALTERNATIVE THEORETICAL PARADIGMS IN MANUFACTURING STRATEGY

Testing and cross‐validation of theories and paradigms are necessary to advance the field of manufacturing strategy. When the findings of one study are also obtained in other studies, using entirely different databases, we become more confident in the results. Replication alleviates concerns about spurious results and is one motivation for this study. We examine aspects of the tradeoffs concept, production competence paradigm, and a manufacturing strategy taxonomy framework. In regard to the tradeoffs concept, we found evidence of tradeoffs between some, but certainly not all, manufacturing capabilities of quality, cost, delivery, and customization. The relationships get sharper when controlling for process choice. For example, the tradeoff between cost and customization is particularly strong between plants that have different process choices. We find that such tradeoffs can change, or even disappear, however, once the process choice is in place. With respect to the production competence paradigm, our analysis shows a statistically significant correlation between production competence and operations performance in batch shops, but not in plants with other process choices. Finally, using variables similar to those of Miller and Roth, our data produced three similar clusters even though their unit of analysis was much more macro than ours. Controlling for process choice is consistent with the current manufacturing strategy literature that emphasizes dynamic development of capabilities within the context of path dependencies. A major argument of this strand of research is that operations decisions not only affect current capabilities, but also set the framework for development of capabilities in the future. That being the case, controlling for process choice (or other factors such as industry or markets) should contribute to the understanding of capability‐development paths adopted by different manufacturing plants. In short, we found at least partial support for each of the theories examined here, even though the theories seem on the surface to be contradictory and mutually exclusive. Controlling for process choice or other measures of dependency goes a long way in uncovering consistency across different theories and empirical studies in operations management.     

Behaviorally anchored competencies: evaluation tool for training via distance

The purpose of the study was to evaluate and measure perceived learning in a training program delivered via distance education. The program was entitled: Course Design for the Digital Age: Instructional Design and Materials Conversion. The study documents the growth in distance education core competencies of professionals in Costa Rica using a competency-based behaviorally anchored instrument. The study uses both qualitative and quantitative methods of data collection and analysis. The resulting scores provide outcome assessment measures useful for researchers and practitioners for documenting the results of self-assessment and comparing observable behaviors of competence.     

Bayesian coverage optimization models

Finding a subset collection that provides optimal population coverage is a frequently encountered deterministic problem. A random sample is often used to formulate the optimal coverage (OC) model, which is then used to select the subsets that provide the estimated optimal population coverage. Such problems are ubiquitous and occur in both the public and private sectors; examples include media selection, placement of municipal services such as sirens and waste dumps, and reserve site selection. Conceptualizing sample elements as counts in a contingency table, we show how decision-makers can combine prior information with sample data to help formulate OC models. We consider conjugate and vague priors with classical and empirical Bayesian interpretations. We show that the predictive approach yields a common marketing exposure model that has previously been justified empirically. Finally, we demonstrate the potential importance of our results on problems generated from a well-known example from the literature.     

Understanding the Nature and Extent of Farm and Ranch Diversification in North America*

Abstract Pressure to adopt enhanced production technologies, changing government support policies, increasing and more diverse competition, and changing markets have posed economic challenges to North American farmers over the past two decades. As a response, farmers are adjusting their production model by incorporating agricultural related enterprises. Although there is evidence that farm diversification is occurring throughout North America, there is a dearth of scientific information regarding the types of enterprises being developed and used in this context. This study aims to fill this void by exploring the extent of farm diversification by identifying and describing eight types of enterprises that farmers and ranchers are using. It was found that levels of diversification are often dependent on operating and management attributes and owner characteristics, such as the number of family members working on the farm and the number of days that the farmer's spouse works off the farm.