Bias Reduction through First-order Mean Correction, Bootstrapping and Recursive Mean Adjustment

Standard methods of estimation for autoregressive models are known to be biased in finite samples, which has implications for estimation, hypothesis testing, confidence interval construction and forecasting. Three methods of bias reduction are considered here: first-order bias correction, FOBC, where the total bias is approximated by the O(T^-1) bias; bootstrapping; and recursive mean adjustment, RMA. In addition, we show how first-order bias correction is related to linear bias correction. The practically important case where the AR model includes an unknown linear trend is considered in detail. The fidelity of nominal to actual coverage of confidence intervals is also assessed. A simulation study covers the AR(1) model and a number of extensions based on the empirical AR(p) models fitted by Nelson & Plosser (1982). Overall, which method dominates depends on the criterion adopted: bootstrapping tends to be the best at reducing bias, recursive mean adjustment is best at reducing mean squared error, whilst FOBC does particularly well in maintaining the fidelity of confidence intervals.     

Value dimensions,cultural differences,and the prediction of perceived quality of life

This research sought to identify the dimensional structure of values, their relationship to perceived QOL, and to examine cultural differences in value systems. A sample of 200 respondents was asked to provide direct, indirect, and importance ratings of a range of values. It was found that these could be adequately represented by seven dimensions, and that comparable dimensions were obtained from all three sets of value measures. This finding was replicated by alternative analyses, and also replicates previous research, providing strong evidence for the generality of the structure. Some inconsistent differences in values were found between the three ethnic groups (European, Maori, and Polynesian) that comprised the sample, but it was concluded that there were no clear cultural differences in values. No cultural differences were found in QOL measures also. Some possible explanations of these results are discussed. Value dimensions for direct and indirect value measures were found to be useful predictors of QOL, with close, personal dimensions generally being the best predictors. Value importance dimensions were not found to be useful QOL predictors, and it is proposed that future research should focus on aspiration measures.     

Gambling participation in Australia: findings from the national Household Expenditure Survey

Regression modeling is used to predict gambling patterns in Australia on the basis of the unit record files underlying the Australian Bureau of Statistics’ Household Expenditure Survey of 6,892 households. The four largest categories of gambling expenditure are examined, namely: lottery tickets, lotto-type games and instant lottery (scratch cards), TAB (pari-mutuel wagering) and related on course betting, and poker (slot) machines and ticket machines. Determining factors analyzed include the source and level of household income, family composition and structure, welfare status, gender, age, ethnicity and geographic location. Apart from the determinants of expenditure varying widely across the different types of gambling activity, the results generally indicate that the source of household income is more important than the level of income and that household composition and regional location are likewise significant in determining gambling expenditure.      

Toward a Culturally Informed Rehabilitation Treatment Model for American Indian/Alaska Native Veterans

American Indians and Alaska Natives (AI/AN) have a long tradition of military service, allying with Western forces in North America since the 1700s. It is hardly surprising, therefore, that AI/AN veterans experience higher rates of overall disability and service-related disability than veterans of other races and ethnicities. It is not clear, however, that AI/AN veterans with disabilities are receiving effective, culturally informed rehabilitation services. This article examines the incidence of disability among contemporary AI/AN veterans, considers barriers to effective treatment, and points out model programs tailored to the particular needs of this population, with attention to the historical and cultural context of AI/AN military service.     

Resources,homophily, and dependence: Organizational attributes and asymmetric ties in human service networks

This paper examines the effects of organizational attributes on power/dependence relations in interorganizational dyads. Exchange and homophily theories are discussed as two alternative perspectives on the processes that give rise to such effects. The data pertain to interagency ties in three community-based networks of youth service agencies and are analyzed via a new strategy of linear modeling dyadic relations. The results of the analysis suggest that size, administrative position, and justice system connections condition the extent to which an agency initiates and receives ties of influence, assistance, and support. Moreover, these relations are more frequent between agencies with similar treatment ideologies and client racial makeup. Finally, size and justice system access are found to reduce agency dependence on a network's administrative core. In the course of the discussion, a number of related issues and findings are discussed.     

Engaging Indigenous Communities: Towards a Policy Framework for Indigenous Community Justice Programmes

Community engagement has come to the fore as a policy and programme approach that seeks to connect citizens both with each other and with government in order to deliver improved social and economic opportunities and outcomes. This model has become a key aspect of the intervention approach within Indigenous communities and is seen to have particular application in addressing community justice issues. This article examines a suite of community justice initiatives being used in Indigenous communities in Australia with a view to ascertaining how the principles of community engagement are operationalized. The article draws on this information and argues that community engagement is only one aspect of a number of community‐oriented justice initiatives currently being applied. These initiatives range from concepts of community as a location, community as an interest group, and the leveraging of community capital so as to tap into and build better and stronger relationships. In so doing, the latter attempts to increase the social infrastructure, resources and capacity of communities. However, despite government attention in this area, there is a lack of a policy and programmatic framework to guide a coherent and apposite approach to issues of community in specific policy settings. The article contributes to the development of a framework that begins the process of differentiating and assessing justice administration interventions.     

Fishing in Urban New Jersey: Ethnicity Affects Information Sources,Perception, and Compliance

Recreational and subsistence angling are important aspects of urban culture for much of North America where people are concentrated near the coasts or major rivers. Yet there are fish and shellfish advisories for many estuaries, rivers, and lakes, and these are not always heeded. This paper examines fishing behavior, sources of information, perceptions, and compliance with fishing advisories as a function of ethnicity for people fishing in the Newark Bay Complex of the New York–New Jersey Harbor. We test the null hypothesis that there were no ethnic differences in sources of information, perceptions of the safety of fish consumption, and compliance with advisories. There were ethnic differences in consumption rates, sources of information about fishing, knowledge about the safety of the fish, awareness of fishing advisories or of the correct advisories, and knowledge about risks for increased cancer and to unborn and young children. In general, the knowledge base was much lower for Hispanics, was intermediate for blacks, and was greatest for whites. When presented with a statement about the potential risks from eating fish, there were no differences in their willingness to stop eating fish or to encourage pregnant women to stop. These results indicate a willingness to comply with advisories regardless of ethnicity, but a vast difference in the base knowledge necessary to make informed risk decisions about the safety of fish and shellfish. Although the overall median income level of the population was in the $25,000–34,999 income category, for Hispanics it was on the border between $15,000–24,999 and $25,000–34,999.     

Probabilistic Reliability Modeling for Oil Exploration & Production (E&P) Facilities in the Tallgrass Prairie Preserve

The aging domestic oil production infrastructure represents a high risk to the environment because of the type of fluids being handled (oil and brine) and the potential for accidental release of these fluids into sensitive ecosystems. Currently, there is not a quantitative risk model directly applicable to onshore oil exploration and production (E&P) facilities. We report on a probabilistic reliability model created for onshore exploration and production (E&P) facilities. Reliability theory, failure modes and effects analysis (FMEA), and event trees were used to develop the model estimates of the failure probability of typical oil production equipment. Monte Carlo simulation was used to translate uncertainty in input parameter values to uncertainty in the model output. The predicted failure rates were calibrated to available failure rate information by adjusting probability density function parameters used as random variates in the Monte Carlo simulations. The mean and standard deviation of normal variate distributions from which the Weibull distribution characteristic life was chosen were used as adjustable parameters in the model calibration. The model was applied to oil production leases in the Tallgrass Prairie Preserve, Oklahoma. We present the estimated failure probability due to the combination of the most significant failure modes associated with each type of equipment (pumps, tanks, and pipes). The results show that the estimated probability of failure for tanks is about the same as that for pipes, but that pumps have much lower failure probability. The model can provide necessary equipment reliability information for proactive risk management at the lease level by providing quantitative information to base allocation of maintenance resources to high-risk equipment that will minimize both lost production and ecosystem damage.     

Social Support Networks of African-American Children Attending Head Start: A Longitudinal Investigation of Structural and Supportive Network Characteristics

This study examined the stability and coherence of African‐American children's social support networks. Participants included a total of 106 3‐ to 4‐year‐old children attending Head Start centers located in the southeast. Children completed a social network interview in two consecutive years at the Head Start centers. These interviews tapped multiple dimensions of the support network including social embeddedness, proportion of the network providing support, and perceived support. Analyses focused on both the rank‐order stability of children with respect to network characteristics as well as stability of network relationships (the same individuals included in the network at both time periods). Results indicated age‐related increases in network size for adult and child categories, network size across three support domains, proportion of support scores, and perceived support from adults. In addition to age‐related changes, analyses revealed considerable rank‐order stability with respect to structural network dimensions, but very little rank‐order stability in proportion of support and perceived support scores. In contrast, both structural and supportive components of the children's networks were shown to be coherent over a one‐year period when specific network member relationships were examined. Discussion highlights both continuities and discontinuities in young children's social networks, and how data obtained in this study contribute to theory building and the systematic examination of African‐American children's emerging social networks.     

The Cat and Mouse Game at the Mexico‐U.S. Border: Gendered Patterns and Recent Shifts1

This paper provides new insights into the process of undocumented border crossing by examining both men and women in the process. We investigate differences in the ways in which men and women make their way across the well‐guarded Mexico‐U.S. border, and the extent to which men and women by the end of the 1990s were similar to, or different from, their counterparts who crossed before 1986 and the implementation of immigration policy designed to reduce undocumented migration. We find substantial differences in how men and women crossed the border without legal documents and in their chances of being apprehended. Our analysis makes clear that shifts in U.S. immigration policy after 1986 have led to women's greater reliance on the assistance of paid smugglers to cross without documents but men were more likely to cross alone. Moreover, immediately after 1986, women on first U.S. trips faced higher risks of being apprehended compared to women who migrated in the early 1980s, but men faced lower risks. After accumulating some U.S. experience, however, both women and men faced lower risks of being detected after 1986 compared to earlier in that decade.