SOME COMMENTS ON “A SYSTEMS PERSPECTIVE ON MATERIALS REQUIREMENTS PLANNING”*

We believe there are some serious deficiencies in the Morecroft article on MRP problems which appeared in a recent issue of this journal. The article, at the most, shows that MRP, inappropriately imposed on an existing production system, can result in undesirable system performance. This does not represent a new or startling conclusion. Four problem areas in the article are discussed, and suggested alternative approaches are offered.     

Empirical Prediction Intervals for County Population Forecasts

Population forecasts entail a significant amount of uncertainty, especially for long-range horizons and for places with small or rapidly changing populations. This uncertainty can be dealt with by presenting a range of projections or by developing statistical prediction intervals. The latter can be based on models that incorporate the stochastic nature of the forecasting process, on empirical analyses of past forecast errors, or on a combination of the two. In this article, we develop and test prediction intervals based on empirical analyses of past forecast errors for counties in the United States. Using decennial census data from 1900 to 2000, we apply trend extrapolation techniques to develop a set of county population forecasts; calculate forecast errors by comparing forecasts to subsequent census counts; and use the distribution of errors to construct empirical prediction intervals. We find that empirically-based prediction intervals provide reasonably accurate predictions of the precision of population forecasts, but provide little guidance regarding their tendency to be too high or too low. We believe the construction of empirically-based prediction intervals will help users of small-area population forecasts measure and evaluate the uncertainty inherent in population forecasts and plan more effectively for the future.     

Modeling Synergy and Learning under Multiple Advanced Manufacturing Technologies

The advent of the wide variety of new, highly integrated, advanced manufacturing technologies available for acquisition by a firm's managers has brought to light an accompanying set of unexpected issues. These issues include expectations for the benefits and costs of these technologies, determining the appropriate order of implementation and finding a way to justify acquisition when many of the benefits are a function of the technology's learning and synergistic effects on other operations and technologies. We present here a model that captures the interaction effects of these highly integrated technologies and discuss the data requirements for application of the construct. We then illustrate the model's workings with a number of multitechnology examples and show the danger of ignoring the synergistic and learning effects of these technologies when considering their acquisition.     

Postmigration Living Difficulties,Help-Seeking and Community Resilience in the Initial Stages of Migration: Coproducing Community Practice with Recent Irish Migrants to London

This article describes a community-based participatory action research (CBPAR) project that examined the postmigration living difficulties (PMLD), help-seeking and community resilience of recent Irish migrants to London (n = 176). The majority of respondents were young adults, in managerial or professional occupations and in good or very good health. Mixed methods indicate inadequate planning for relocation and poor social support as the main difficulties in the initial stages of migration. Community factors promoting resilience included employment opportunities, local and transnational supports, and cultural familiarity and acceptance. Community participation in the action orientated phase of this CBPAR is discussed.     

Developmental Change in Action Perception: Is Motor Experience the Cause?

Human actions are complex stimuli containing several perceptual dimensions an observer could attend to. Research indicates that attention to the perceptual dimensions of action undergoes a process of perceptual narrowing between 4 and 10 months, during which infants’ attention to configural and temporal information in action decreases over time, while attention to hand information is maintained. This research explored whether infants’ active experience with grasping is related to perceptual narrowing in action. Across two studies, we tested 6‐month‐old infants’ attention to changes in these action dimensions and also assessed their grasping ability. Infants who were more proficient at grasping showed a pattern more consistent with perceptual narrowing (decreasing attention to configural and temporal information) relative to those less proficient at grasping, especially for attention to configural information. In addition, attention to hand information appears to undergo U‐shaped development between 4 and 10 months, as 6‐month‐olds did not recover attention to the hand change. These findings add to a growing body of research showing that infants’ motor experience broadly influences their perception of others’ action and may follow a complex developmental pathway that diverges from perceptual narrowing over the first year.     

On the Road to Resilience: The Help‐Seeking Experiences of Irish Emigrant Survivors of Institutional Abuse

Understanding how survivors of complex trauma navigate towards resources can inform the design of interventions and health promotion strategies. However, there are little data on the resilience and help‐seeking experiences of this group or others who have experienced institutional abuse in childhood. This empirical study sets out to illustrate the help‐seeking experiences of Irish emigrant survivors of institutional childhood abuse (ICA). Twenty‐two survivors of ICA were purposefully recruited from community organisations in the UK and data were collected via semi‐structured interviews. As a result of negative initial help‐seeking experiences in Ireland, most participants engaged in long periods of self‐management and disclosed information about their childhood as part of a redress scheme in later life. Outside of this scheme, turning points, such as illness or family problems, and the needs of children were influential in seeking help. Peer support networks played an important role as a trusted signposting pathway towards formal interventions. Participants identified interpersonal barriers to formal help‐seeking as helping professionals' failure to share control, insensitivity to identity loss and literacy issues, and the lack of explicit boundaries. The paper concludes with a discussion about the implications for research and future practice.

‘This empirical study sets out to illustrate the help‐seeking experiences of Irish emigrant survivors of institutional childhood abuse’

Key Practitioner Messages:

• Turning points, such as illness and bereavement, and the desire to provide for children, influence the help‐seeking of survivors of ICA.
• Irish emigrant survivors of ICA cite failure to share control, insensitivity to identity loss, literacy issues and the lack of explicit boundaries as barriers to help‐seeking.
• General awareness of ICA can help practitioners in low‐threshold services prevent against culturally insensitive practice.
• Peer support networks can provide uniquely trusted signposting towards formal interventions.

     

Insights into the appropriate level of disaggregation for efficient time series model forecasting

This paper provides a potentially valuable insight on how to assess if the forecasts from an autoregressive moving average model based on aggregated data could be substantially improved through disaggregation. It is argued that, theoretically, the absence of moving average (MA) terms indicates that no forecasting efficiency improvements can be achieved through disaggregation. In practice, it is found that there is a strong correlation between the statistical significance of the MA component in the aggregate model and the magnitude of the forecast mean square error (MSE) decreases that can be achieved through disaggregation. That is, if a model includes significant MA terms, the forecast MSE improvements that may be gained from disaggregation could be substantial. Otherwise, they are more likely to be relatively small or non-existent.     

Notes on authors

Social network analysis (SNA), a method which can be used to explore networks in various contexts, has received increasing attention. Drawing on the development of European smoke-free policy, this paper explores how a mixed-method approach to SNA can be utilised to investigate a complex policy network. Textual data from public documents, consultation submissions and websites were extracted, converted and analysed using plagiarism detection software and quantitative network analysis and qualitative data from public documents and 35 interviews were thematically analysed. While the quantitative analysis enabled understanding of the network’s structure and components, the qualitative analysis provided in-depth information about specific actors’ positions, relationships and interactions. The paper establishes that SNA is suited to empirically testing and analysing networks in EU policy-making. It contributes to methodological debates about the antagonism between qualitative and quantitative approaches and demonstrates that qualitative and quantitative network analysis can offer a powerful tool for policy analysis.     

Social Movements and Tactical Choice

For much of the past 40 years, the study of social movement tactics has viewed organizers' choices as driven by a desire to maximize efficacy and efficiency within a context of scarce resources and structural constraints. As sociologists increasingly turned toward culture, a new orientation emerged to view tactical choice as a process of gathering, interpreting, and evaluating information within dynamic, uncertain, and often‐contradictory contexts. The importance of the cultural turn has been amply demonstrated in studies of such things as identities, emotions, and collective action frames, but the full implications of its insights continue to be discovered. Four insights in particular warrant greater attention: many core concepts in the study of social movements have an interpretive, subjective, and contingent nature; tactics are a means of communication; social structures are imbued with culture, and culture is thoroughly structured; and social movements sometimes behave irrationally, and what appears to be irrational behavior often is in fact rational. I briefly discuss three areas of scholarship – collective identities, diffusion, and institutional fields – that demonstrate innovative ways that sociologists continue to combine and incorporate these insights and point the way toward a more sophisticated understanding of social movements and tactical choice.