An Evaluation of Persons per Household (PPH) Estimates Generated by the American Community Survey: A Demographic Perspective

The American Community Survey (ACS) is a U.S. Census Bureau product designed to provide accurate and timely demographic and economic indicators on an annual basis for both large and small geographic areas within the United States. Operational plans call for ACS to serve not only as a substitute for the decennial census long-form, but as a means of providing annual data at the national, state, county, and subcounty levels. In addition to being highly ambitious, this approach represents a major change in how data are collected and interpreted. Two of the major questions facing the ACS are its functionality and usability. This paper explores the latter of these two questions by examining “persons per household (PPH),” a variable of high interest to demographers and others preparing regular post-censal population estimates. The data used in this exploration are taken from 18 of the counties that formed the set of 1999 ACS test sites. The examination proceeds by first comparing 1-year ACS PPH estimates to Census 2010 PPH values along with extrapolated estimates generated using a geometric model based on PPH change between the 1990 and 2000 census counts. Both sets of estimates are then compared to annual 2001–2009 PPH interpolated estimates generated by a geometric model based on PPH from the 2000 census to the 2010 census. The ACS PPH estimates represent what could be called the “statistical perspective” because variations in the estimates of specific variables over time and space are viewed largely by statisticians with an eye toward sample error. The model-based PPH estimates represent a “demographic perspective” because PPH estimates are largely viewed by demographers as varying systematically and changing relatively slowly over time, an orientation stemming from theory and empirical evidence that PPH estimates respond to demographic and related determinants. The comparisons suggest that the ACS PPH estimates exhibit too much “noisy” variation for a given area over time to be usable by demographers and others preparing post-censal population estimates. These findings should be confirmed through further analysis and suggestions are provided for the directions this research could take. We conclude by noting that the statistical and demographic perspectives are not incompatible and that one of the aims of our paper is to encourage the U.S. Census Bureau to consider ways to improve the usability of the 1-year ACS PPH estimates.     

The stratification of universities: Structural inequality in Canada and the United States

This paper conceives national systems of higher education as stratified populations of organizations. This stratification is a structural component of ‘horizontal inequality’ in higher education, and may be exacerbated by current pressures for colleges and universities to compete for resources and status. To explore this structural inequality, we compare the level of stratification in financial resources across four-year institutions in Canada and the United States over a 35-year period (1971–2006). Our analyses provide a first-look at this form of stratification, employing Gini coefficients, Lorenz curves, and boxplots. Our results provide new and compelling evidence of increasing structural stratification, even in Canada's predominantly publicly funded postsecondary system. Findings indicate that the distribution of resources is far more stratified in the American system, and that both systems have become more stratified over time. We conclude by situating structural inequality within more general processes of stratification in education.     

Two-stage hierarchical modeling for analysis of subpopulations in conditional distributions

In this work, we develop modeling and estimation approach for the analysis of cross-sectional clustered data with multimodal conditional distributions where the main interest is in analysis of subpopulations. It is proposed to model such data in a hierarchical model with conditional distributions viewed as finite mixtures of normal components. With a large number of observations in the lowest level clusters, a two-stage estimation approach is used. In the first stage, the normal mixture parameters in each lowest level cluster are estimated using robust methods. Robust alternatives to the maximum likelihood estimation are used to provide stable results even for data with conditional distributions such that their components may not quite meet normality assumptions. Then the lowest level cluster-specific means and standard deviations are modeled in a mixed effects model in the second stage. A small simulation study was conducted to compare performance of finite normal mixture population parameter estimates based on robust and maximum likelihood estimation in stage 1. The proposed modeling approach is illustrated through the analysis of mice tendon fibril diameters data. Analyses results address genotype differences between corresponding components in the mixtures and demonstrate advantages of robust estimation in stage 1.     

The deterministic EPQ with partial backordering: A new approach

Several authors have developed models for the EOQ when only a percentage of stockouts will be backordered. Most of these models are complicated, with equations unlike those for the EOQ with full backordering. In this paper we extend work by Pentico and Drake [The deterministic EOQ with partial backordering: a new approach. European Journal of Operational Research 2008; in press] that developed equations for the EOQ with partial backordering that are more like those for the EOQ with full backordering to develop a comparable model for the EPQ with partial backordering.     

Manufacturing network configuration in supply chains with product recovery

Efficient implementation of product recovery requires appropriate network structures. In this paper, we study the network design problem of a firm that manufactures new products and remanufactures returned products in its facilities. We examine the capacity decisions and expected performance of two alternative manufacturing network configurations when demand and return flows are both uncertain.     

NUSAP Method for Evaluating the Data Quality in a Quantitative Microbial Risk Assessment Model for Salmonella in the Pork Production Chain

The numeral unit spread assessment pedigree (NUSAP) system was implemented to evaluate the quality of input parameters in a quantitative microbial risk assessment (QMRA) model for Salmonella spp. in minced pork meat. The input parameters were grouped according to four successive exposure pathways: (1) primary production (2) transport, holding, and slaughterhouse, (3) postprocessing, distribution, and storage, and (4) preparation and consumption. An inventory of 101 potential input parameters was used for building the QMRA model. The characteristics of each parameter were defined using a standardized procedure to assess (1) the source of information, (2) the sampling methodology and sample size, and (3) the distributional properties of the estimate. Each parameter was scored by a panel of experts using a pedigree matrix containing four criteria (proxy, empirical basis, method, and validation) to assess the quality, and this was graphically represented by means of kite diagrams. The parameters obtained significantly lower scores for the validation criterion as compared with the other criteria. Overall strengths of parameters related to the primary production module were significantly stronger compared to the other modules (the transport, holding, and slaughterhouse module, the processing, distribution, and storage module, and the preparation and consumption module). The pedigree assessment contributed to select 20 parameters, which were subsequently introduced in the QMRA model. The NUSAP methodology and kite diagrams are objective tools to discuss and visualize the quality of the parameters in a structured way. These two tools can be used in the selection procedure of input parameters for a QMRA, and can lead to a more transparent quality assurance in the QMRA.     

The Surgical Scheduling Problem: Current Research and Future Opportunities

This paper reviews the general problem of surgical scheduling. We organize the literature based on the time frame or planning horizon of the schedule into six categories: capacity planning, process reengineering/redesign, the surgical services portfolio, procedure duration estimation, schedule construction, and schedule execution, monitoring, and control. We survey past work and suggest topics for potential future research in each of those areas.     

Nonbinding recommendations: the relative effects of focal points versus uncertainty reduction on bargaining outcomes

This article focuses on the effects of nonbinding recommendations on bargaining outcomes. Recommendations are theorized to have two effects: they can create a focal point for final bargaining positions, and they can decrease outcome uncertainty should dispute persist. While the focal point effect may lower dispute rates, the uncertainty reduction effect is predicted to do the opposite for risk-averse bargainers. Which of these effects dominates is of critical importance in the design of alternative dispute resolution (ADR) procedures, which are increasingly utilized in a variety of settings. We theoretically examine the effects of recommendations on the contract zone using a framework which allows bargainers’ final positions to influence a binding outcome should negotiations fail. This provides a more stringent test of focal points than previously considered. We also present data from controlled laboratory experiments consistent with our model. Recommendations are empirically shown to influence final bargaining positions and negotiated settlement values. In fact, recommendations significantly reduce dispute rates, even where they are completely ignored in final-stage arbitration. This highlights a potentially significant role for the use of nonbinding procedures, such as mediation, as a preliminary stage in more efficient ADR procedures.     

Poverty,Government Policy and Public Opinion in Britain and Israel: A Comparative Analysis

What are the effects of public opinion on social welfare policies? To what extent is increased financial strain associated with stronger support for anti‐poverty policies? This article tests welfare state theory by comparing poverty, government policy and public opinion on poverty in the UK and Israel, based on rich and detailed comparable survey data on the conditions of the poor in both countries. The results show that, despite similar levels of income poverty and inequality, the poor have a considerably lower standard of living in Israel than the UK. There is considerably greater public support for the poor in Israel but limited government action to end poverty, whereas in the UK there is more limited public support for the poor but significant government action on poverty and exclusion. In both countries there appears to be only a limited connection between social solidarity with the poor and the political elite's rhetoric and action.     

ADHD and its comorbidity: an example of gene–environment interaction and its implications for child and family social work

In many of their cases, child and family social workers, particularly those involved with abuse and neglect, will find themselves also working with children who have been diagnosed with attention deficit hyperactivity disorder (ADHD). The paper reviews current understandings and debates about the nature and causes of ADHD. Although modern evidence suggests the neurobiological basis of the condition and the effectiveness of medication in treating the behaviour, it is also recognized that the quality of the child's caregiving and social environment plays a significant role in the aetiology, maintenance and treatment of ADHD. Recognizing the part that psychosocial elements play in understanding the condition, child and family social workers can be valued members of multidisciplinary teams treating ADHD in which they offer support to parents, helping them to understand and manage their ADHD‐diagnosed child.