A Bootstrap Stationarity Test for Predictive Regression Invalidity

In order for predictive regression tests to deliver asymptotically valid inference, account has to be taken of the degree of persistence of the predictors under test. There is also a maintained assumption that any predictability in the variable of interest is purely attributable to the predictors under test. Violation of this assumption by the omission of relevant persistent predictors renders the predictive regression invalid, and potentially also spurious, as both the finite sample and asymptotic size of the predictability tests can be significantly inflated. In response, we propose a predictive regression invalidity test based on a stationarity testing approach. To allow for an unknown degree of persistence in the putative predictors, and for heteroscedasticity in the data, we implement our proposed test using a fixed regressor wild bootstrap procedure. We demonstrate the asymptotic validity of the proposed bootstrap test by proving that the limit distribution of the bootstrap statistic, conditional on the data, is the same as the limit null distribution of the statistic computed on the original data, conditional on the predictor. This corrects a long-standing error in the bootstrap literature whereby it is incorrectly argued that for strongly persistent regressors and test statistics akin to ours the validity of the fixed regressor bootstrap obtains through equivalence to an unconditional limit distribution. Our bootstrap results are therefore of interest in their own right and are likely to have applications beyond the present context. An illustration is given by reexamining the results relating to U.S. stock returns data in Campbell and Yogo (2006 Campbell, J. Y. and Yogo, M. (2006), “Efficient Tests of Stock Return Predictability,” Journal of Financial Economics, 81, 27–60.[Crossref], [Web of Science ®] , [Google Scholar]). Supplementary materials for this article are available online.     

The Modeling and Seasonal Adjustment of Weekly Observations

Several important economic time series are recorded on a particular day every week. Seasonal adjustment of such series is difficult because the number of weeks varies between 52 and 53 and the position of the recording day changes from year to year. In addition certain festivals, most notably Easter, take place at different times according to the year. This article presents a solution to problems of this kind by setting up a structural time series model that allows the seasonal pattern to evolve over time and enables trend extraction and seasonal adjustment to be carried out by means of state-space filtering and smoothing algorithms. The method is illustrated with a Bank of England series on the money supply.     

Strong consistency of presmoothed Kaplan–Meier integrals when covariables are present

It is known that the Kaplan–Meier estimation may be improved via presmoothing methods. In this article, we introduce an extended presmoothed Kaplan–Meier estimator in the presence of covariates. The main result is the strong consistency of general empirical integrals based on such an estimator. As applications, one can obtain a consis-tent multivariate empirical distribution under censoring, and also can obtain a consistent estimation of regression parameters. We illustrate the new estimation methods through simulations and real data analysis.     

Do social work education,job description,and cultural competence foster child‐welfare caseworkers' therapeutic alliances?

We explored whether the strength of caseworkers' engagement with families in the child‐welfare system was associated with the caseworkers' academic degrees, job responsibilities and environments, and/or ethnicity. We extracted data from a national data set describing 1,714 caseworkers. Results confirmed significant association between caseworkers' confidence in their engagement with families and (a) master's‐ and bachelor's‐level social work education, (b) adequate supervision at work, (c) cultural‐diversity training, (d) job focus (screening/investigation, out‐of‐home placement, or reunification), and (e) homogeneous race/ethnicity of caseworker and client.     

What’s disability got to do with it? Changing constructions of Oscar Pistorius before and after the death of Reeva Steenkamp

Traditionally disability has been viewed in the popular imagination as either a highly positive or highly negative phenomenon. Disability and disabled people deserve to be seen in an integrated, holistic way and to have recognised as much diversity as characterises the human condition. The recent case of Oscar Pistorius fatally shooting Reeva Steenkamp has highlighted this tendency. Before this incident, Pistorius’ disability was viewed in a predominantly positive light. He had been described as a ‘supercrip’ who had, despite his physical impairments, ‘overcome’ his mobility limitations and was consequently attributed heroic status by some. However, after this fatal incident, the portrayal of Pistorius’ disability has, perhaps inevitably, shifted. This paper will offer possible psychosocial reasons for this tendency to view disability in a binary way.     

Estimation of local demographic variation in a flexible framework for population projections

A cohort component projection of local populations based on sex and single year of age offers great value for planning local services, but demands data beyond the detail available. Local fertility, mortality and migration schedules by age and sex must be estimated sensitively to local variation if the results are to be of greater value than simpler methods of projection. Two approaches are compared, using data for the recent past: (a) direct estimation of local area age-specific schedules of fertility, mortality and migration based on data available to the national statistical agency; (b) graduation of national schedules using only local area population estimates by age, total numbers of births, and total numbers of deaths; age-specific migration is indirectly estimated from successive population estimates. These two approaches are compared with a projection using the same rates for each area. The three projections have been implemented for electoral wards in the Fife local government area of Scotland, using the flexible framework provided by POPGROUP software. Persuasive local population projections based on standard data for standard areas are feasible without the regular publication of migration flows.     

Implementing a triangulation protocol in bereavement research: a methodological discussion

Triangulation is a comparative strategy for examining data that strengthens qualitative and multi-method research. Despite the benefits of triangulation noted in the research methods literature, few concrete models for operationalization of protocols exist. Lack of documentation of explicit triangulation procedures is especially true in the area of bereavement research. This article describes how an interdisciplinary research team implemented a triangulation protocol in a study of the needs of bereaved parents. Triangulation enabled the integration of diverse data sources, methods, and disciplinary perspectives. These processes yielded a more meaningful typology of bereaved parents' needs than would have otherwise been possible. Extending the use of triangulation will enhance multi-faceted understandings of bereavement.     

An Evaluation of Physical Fitness Parameters for Graduate Students

Abstract

Although graduate physical therapy students are taught the principles of fitness for incorporation into their professional lives, they have difficulty finding the time to implement these principles during graduate school. The authors studied 3 successive classes of graduate physical therapy students at the beginning and ending of their respective programs. They found that the women's percentages of body fat were significantly greater over the period of the study. The men's lower extremity strength decreased at the slower speeds (60 degrees/second), and the women showed increased strength at the higher speeds (180 and 240 degrees/second, respectively). Male grip strength significantly increased over the period of the study. To decrease students' percentages of body fat and increase their strength, the authors asserted that physical therapy students should be allowed more time to participate in fitness activities during their graduate school years.     

Social ecological complex adaptive systems: a framework for research on payments for ecosystem services

The environment is both a setting for and a product of human interactions. Understanding the dynamic nature of human-environment interactions is critical for mitigating the impacts of human induced environmental change and understanding how the environment shapes social systems. Current research has focused on the reduced ability of many natural systems to provide ecosystem services and the subsequent impact on human well-being. Furthermore, there has been a proliferation of cases analyzing the impacts of payment programs designed to enhance ecosystem services. However, analyses that link environmental policies through to their ecological results are not common and methods to do so are not thoroughly developed. To better analyze these interactions, a theory or framework is necessary. This article presents a framework of social ecological complex adaptive systems (SECAS). The framework links structuration theory from social science with the theories of complex adaptive systems from ecology to provide an enhanced understanding of the human drivers and responses to environmental change. The framework is presented as a recursive process where social and ecological systems are both the medium for and product of social action and ecological disturbance. A case study of Costa Rica’s ecosystem service payment program is presented as a demonstration of empirical applicability. This framework is proposed as a method to evaluate payments for ecosystem services, conservation policies, urban ecosystems, and for land use change in general.