Sample moments of the autocorrelations of moving average processes and a modification to bartlett'sasymptotic variance formula

In this paper we express the sample autocorrelations for a moving average process of order q as a function of its own theoretical autocorrelations and the sample autocorrelations for the generating white noise series. Approximate analytic expressions are then obtained forthe moments of the sample autocorrelations of the moving average process.

Using these expressions, together with numerical evidence, we show that Bartlett's asymptotic formula for the variance of the sample autocorrelations of moving average processes, which is used widely in identifying these processes, is a large overestimate when considering finitesample sizes.

Our approach is for motivational purposes and so is purely formal, the amount of mathematics presented being kept to a minimum.     

Nonparametric Regression as an Example of Model Choice

Nonparametric regression can be considered as a problem of model choice. In this article, we present the results of a simulation study in which several nonparametric regression techniques including wavelets and kernel methods are compared with respect to their behavior on different test beds. We also include the taut-string method whose aim is not to minimize the distance of an estimator to some “true” generating function f but to provide a simple adequate approximation to the data. Test beds are situations where a “true” generating f exists and in this situation it is possible to compare the estimates of f with f itself. The measures of performance we use are the L²- and the L^∞-norms and the ability to identify peaks.     

Connecting child care quality to child outcomes: drawing policy lessons from nonexperimental data

Effective early childhood intervention and child care policies should be based on an understanding of the effects of child care quality and type on child well-being. This article describes methods for securing unbiased estimates of these effects from nonexperimental data. It focuses on longitudinal studies like the one developed by the National Institute of Child Health and Human Development's Early Child Care Research Network. This article first describes bias problems that arise in analyses of nonexperimental data and then explains strategies for controlling for biases arising from parental selection of child care. Next, it comments on attrition in longitudinal studies and outlines some strategies for addressing possible attrition bias. Finally, it discusses the need to translate "effect sizes" derived from these studies into the kinds of cost and benefit information needed by policy makers.     

The significance of place in middle childhood: qualitative research from Wales

The paper presents some key findings of qualitative research with older primary school children in Wales on their attachments to places and cultures. There is discussion of children's perspectives on the global, national and local arenas. We argue both that there are continuities with adult perspectives and that the children's views on place and identity need to be understood in the context of the social location of middle childhood. The study shows children making relatively little use of culturally-filled categories of local, national and global place-identifications. The differences they articulate are largely framed in terms of divisions between groups of people rather than in the characteristics of place, and generally related back to the self.     

INTEGER GOAL PROGRAMMING IN ADVERTISING MEDIA SELECTION

The media selection decision allocates advertising dollars among competing media so as to optimize promotional and corporate objectives. Linear programming attempts to model this process have been complicated by multiple and often conflicting management goals, the need for integer solutions, and nonlinearities. This study offers a technique that is sufficiently robust to simultaneously handle these problems. An alternative media selection framework is presented and the results of an illustrative application of integer goal programming are discussed. The proposed model improves on linear programming by success fully providing for optimal, integer solutions in settings that more realistically reflect the complexity of the media decision environment.     

Planning participation in public decision making

By posing as specialists in forecasting the future, by arguing the “inevitability of technological progress, and by hiding behind the skirts of public officials, planners in the public sector seek to exercise power without responsibility—power to determine the shape of life for the rest of us. The author attacks this myth of the all- seeing planner and in the process seeks to demolish some of the planners' unwarranted assumptions about “the year 2000”, the future of technology, the affluent society, the age of leisure, etc.     

Toward a dimensional model of risk and protective factors influencing children's early cognitive,social, and emotional development during the COVID-19 pandemic

Variation in infants’ home environment is implicated in their cognitive and psycho-social development. The pandemic has intensified variations in home environments through exacerbating socioeconomic inequalities, and increasing psychological stressors for some families. This study investigates the effects of parental (predominantly maternal) mental health, enriching activities and screen use on 280 24- to 52-month-olds’ executive functions, internalising and externalising problems, and pro-social behaviour; with socioeconomic status and social support as contextual factors. Our results indicate that aspects of the home environment are differentially associated with children’s cognitive and psycho-social development. Parents who experienced sustained mental distress during the pandemic tended to report higher child externalising and internalising problems, and executive function difficulties at follow-up. Children who spent more time engaged in enriching activities with their parents showed stronger executive functions and social competence six months later. Screen use levels during the first year of the pandemic were not associated with outcomes. To mitigate the risk of persistent negative effects for this ‘pandemic generation’ of infants, our study highlights the importance of supporting parents’ mental health. As our results demonstrate the impact of social support on mental health, investing in support services and interventions promoting building support networks are likely to be beneficial.