Refined Inference on Long Memory in Realized Volatility

There is an emerging consensus in empirical finance that realized volatility series typically display long range dependence with a memory parameter (d) around 0.4 (Andersen et al., 2001 Andersen , T. G. , Bollerslev , T. , Diebold , F. X. , Labys , P. ( 2001 ). The distribution of realized exchange rate volatility . Journal of the American Statistical Association 96 ( 453 ): 42 – 55 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]; Martens et al., 2004 Martnes , M. , Van Dijk , D. , De Pooter , M. ( 2004 ). Modeling and forecasting S&P 500 volatility: Long memory, structural breaks and nonlinearity. Tinbergen Institute Discussion Paper 2004-067/4 . [Google Scholar]). The present article provides some illustrative analysis of how long memory may arise from the accumulative process underlying realized volatility. The article also uses results in Lieberman and Phillips (2004 Lieberman , O. , Phillips , P. C. B. ( 2004 ). Expansions for the distribution of the maximum likelihood estimator of the fractional difference parameter . Econometric Theory 20 ( 3 ): 464 – 484 . [Google Scholar], 2005 Lieberman , O. , Phillips , P. C. B. ( 2005 ). Expansions for approximate maximum likelihood estimators of the fractional difference parameter . The Econometrics Journal 8 : 367 – 379 . [Google Scholar]) to refine statistical inference about d by higher order theory. Standard asymptotic theory has an O(n ^?1/2) error rate for error rejection probabilities, and the theory used here refines the approximation to an error rate of o(n ^?1/2). The new formula is independent of unknown parameters, is simple to calculate and user-friendly. The method is applied to test whether the reported long memory parameter estimates of Andersen et al. (2001 Andersen , T. G. , Bollerslev , T. , Diebold , F. X. , Labys , P. ( 2001 ). The distribution of realized exchange rate volatility . Journal of the American Statistical Association 96 ( 453 ): 42 – 55 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) and Martens et al. (2004 Martnes , M. , Van Dijk , D. , De Pooter , M. ( 2004 ). Modeling and forecasting S&P 500 volatility: Long memory, structural breaks and nonlinearity. Tinbergen Institute Discussion Paper 2004-067/4 . [Google Scholar]) differ significantly from the lower boundary (d = 0.5) of nonstationary long memory, and generally confirms earlier findings.     

A bayesian analysis of trend determination in economic time series

In this paper we provide a comprehensive Bayesian posterior analysis of trend determination in general autoregressive models. Multiple lag autoregressive models with fitted drifts and time trends as well as models that allow for certain types of structural change in the deterministic components are considered. We utilize a modified information matrix-based prior that accommodates stochastic nonstationarity, takes into account the interactions between long-run and short-run dynamics and controls the degree of stochastic nonstationarity permitted. We derive analytic posterior densities for all of the trend determining parameters via the Laplace approximation to multivariate integrals. We also address the sampling properties of our posteriors under alternative data generating processes by simulation methods. We apply our Bayesian techniques to the Nelson-Plosser macroeconomic data and various stock price and dividend data. Contrary to DeJong and Whiteman (1989a,b,c), we do not find that the data overwhelmingly favor the existence of deterministic trends over stochastic trends. In addition, we find evidence supporting Perron's (1989) view that some of the Nelson and Plosser data are best construed as trend stationary with a change in the trend function occurring at 1929.     

On constructing sequences estimating the mixing distribution with applications

This paper shows that by minimizing a Chebychev norm a mixing distribution can be constructed which converges weakly to the true mixing distribution with probability one. Deely and Kruse (1968) established a similar result for the supremum norm. For both norms the constructed mixing distribution is computed by solving a linear programming problem, but this problem is considerably smaller when the Chebychev norm is used. Thus a suitable mixing distribution can be constructed from solving a linear programming problem with considerably less computational work than was previously known. To illustrate the application of this simpler procedure it is applied to derive nonparametric empirical Bayes estimates in a simulation study. Some density estimates are also illustrated.     

Imputation and low-rank estimation with Missing Not At Random data

Statistics and Computing - Missing values challenge data analysis because many supervised and unsupervised learning methods cannot be applied directly to incomplete data. Matrix completion based on...     

Textbook Affordability in the Time of COVID-19

Abstract

This article provides a background of the textbook affordability problem affecting students attending United States higher education institutions, both prior to and during the 2019 novel coronavirus disease (COVID-19) pandemic, as well as potential solutions to the problem. Solutions discussed include the availability of open materials in online repositories, publisher responses like inclusive access, institutional incentive programs, and initiatives by library consortia or other statewide programs. The responses of various stakeholders to make textbooks accessible to students during the pandemic are also covered.     

The Bad Enough Mother

ABSTRACT

This is a [de]-composed conversation between the author and a few feminist writers about how a mother’s resistance to interpellating gender is an echoed call to resistance against society’s interpellation of mother. Alongside the words of a few selected 20th- and 21st-century writers, as well as a brief personal and a clinical vignette, the author illustrates ways in which the bad enough mother survives the relentless scrutiny of society—starting with experts like doctors, sociologists, politicians, and psychoanalysts. In turn, she teaches her children survival of the very interpellative tenants of culture that tried to funnel her into a binary-gendered social order.     

Gay,Lesbian, and Heterosexual Couples About to Begin Couples Therapy: An Online Relationship Assessment of 40,681 Couples

We currently have little idea of precisely who goes for couples therapy. This is a report of the results of a validated online assessment of relationship and individual functioning based on 39,251 heterosexual, 1,022 lesbian, and 438 gay couples about to begin couples therapy. Using validated and reliable questionnaires of relationship and individual functioning, this report presents and compares, for each sexual-orientation, the percentage of couples, pre-therapy, who are coping with a variety of relationship problems. To test for the replicability of results, the sample was divided randomly into two subsamples and statistical tests were performed on each sample. Couples initiating therapy suffer from greater distress and many more co-morbidities than has been presumed in previous literature, and same-sex couples present a particular set of both strengths and challenges compared to heterosexual couples. Gay-male and lesbian couples were very different on trust and monogamy, as were heterosexual and lesbian couples. Based on this epidemiologically sized sample, the challenge to our field may be to create interventions with much larger effect sizes than we currently have.     

Enhancing practitioner-led education in social work: developing a secondment project

ABSTRACT

This paper illustrates the development of a secondment project designed to enhance practitioner-led social work education in a Higher Education Institution. The project was developed as part of a Teaching Partnership initiative to establish joint working and standardized approaches to social work education between Higher Education Institutes and Local Authorities across a UK region. Highlighted is how the project utilized a six-stage strategy designed to gather information to produce an evidence-base to support the implementation of a pilot practitioner secondment arrangement. The paper discusses strategies used to gather information from a range of stakeholders to inform the project, the project outcome and some considerations for future secondment arrangements. Contributing to a limited source of literature, challenges and limitations of developing formal secondment arrangements and delivering practitioner-led education in Higher Education Institutes are highlighted. This paper will assist Higher Education Institutes and Local Authorities in the design and implementation of formal secondment arrangements where these are identified as in need of development.