Density Estimation by Total Variation Penalized Likelihood Driven by the Sparsity ℓ1 Information Criterion

Abstract. We propose a non‐linear density estimator, which is locally adaptive, like wavelet estimators, and positive everywhere, without a log‐ or root‐transform. This estimator is based on maximizing a non‐parametric log‐likelihood function regularized by a total variation penalty. The smoothness is driven by a single penalty parameter, and to avoid cross‐validation, we derive an information criterion based on the idea of universal penalty. The penalized log‐likelihood maximization is reformulated as an ?₁‐penalized strictly convex programme whose unique solution is the density estimate. A Newton‐type method cannot be applied to calculate the estimate because the ?₁‐penalty is non‐differentiable. Instead, we use a dual block coordinate relaxation method that exploits the problem structure. By comparing with kernel, spline and taut string estimators on a Monte Carlo simulation, and by investigating the sensitivity to ties on two real data sets, we observe that the new estimator achieves good L ₁ and L ₂ risk for densities with sharp features, and behaves well with ties.     

Limited Information and Advertising in the U.S. Personal Computer Industry

Traditional discrete‐choice models assume buyers are aware of all products for sale. In markets where products change rapidly, the full information assumption is untenable. I present a discrete‐choice model of limited consumer information, where advertising influences the set of products from which consumers choose to purchase. I apply the model to the U.S. personal computer market where top firms spend over $2 billion annually on advertising. I find estimated markups of 19% over production costs, where top firms advertise more than average and earn higher than average markups. High markups are explained to a large extent by informational asymmetries across consumers, where full information models predict markups of one‐fourth the magnitude. I find that estimated product demand curves are biased toward being too elastic under traditional models. I show how to use data on media exposure to improve estimated price elasticities in the absence of micro ad data.     

Optimal Bandwidth Selection in Heteroskedasticity–Autocorrelation Robust Testing

This paper considers studentized tests in time series regressions with nonparametrically autocorrelated errors. The studentization is based on robust standard errors with truncation lag M=bT for some constant b∈(0, 1] and sample size T. It is shown that the nonstandard fixed‐b limit distributions of such nonparametrically studentized tests provide more accurate approximations to the finite sample distributions than the standard small‐b limit distribution. We further show that, for typical economic time series, the optimal bandwidth that minimizes a weighted average of type I and type II errors is larger by an order of magnitude than the bandwidth that minimizes the asymptotic mean squared error of the corresponding long‐run variance estimator. A plug‐in procedure for implementing this optimal bandwidth is suggested and simulations (not reported here) confirm that the new plug‐in procedure works well in finite samples.     

The Emergence of Service Science: Toward Systematic Service Innovations to Accelerate Co‐Creation of Value

The current growth of the service sector in global economies is unparalleled in human history—by scale and speed of labor migration. Even large manufacturing firms are seeing dramatic shifts in percent revenue derived from services. The need for service innovations to fuel further economic growth and to raise the quality and productivity levels of services has never been greater. Services are moving to center stage in the global arena, especially knowledge‐intensive business services aimed at business performance transformation. One challenge to systematic service innovation is the interdisciplinary nature of service, integrating technology, business, social, and client (demand) innovations. This paper describes the emergence of service science, a new interdisciplinary area of study that aims to address the challenge of becoming more systematic about innovating in service.     

Care: A Critical Review of Theory,Policy and Practice

‘Care’ is a source of critical tension in current social theory, and the policy and practice implications of that tension are evidenced in its current prominence on the political agenda of developed welfare states. This article critically appraises current developments in the theory, policy and practice of care, drawing on interdisciplinary developments in political theory, sociology and social policy. Developing feminist and disability‐rights theories, it explores a critical synthesis of conflicting normative and theoretical positions regarding the giving and receiving of care, and of the ethics and justice of care. It examines case studies of current comparative policy developments across a range of different welfare regimes, including the marketization/commodification and de/re‐familiaization of care, exploring ideological and normative trends in the design of contemporary policies. It discusses the impact of theory and policy on the practice of care, looking particularly at the issue of long‐term care for disabled and older adults. Finally, the authors argue for the development of a citizenship‐based approach to care that decouples it from individualistic and paternalistic paradigms that disempower those who give and receive care.     

Black‐market Medicine and Public Opinion Towards the Welfare State: Evidence from Israel

Based on a survey and interviews, this article presents and analyses Israeli public opinion toward black‐market medicine (BMM) and the welfare state. In addition to providing quantitative and qualitative evidence of the existence of under‐the‐table payments in Israel, we suggest various insights into this phenomenon. While most citizens admit that they would consider making under‐the‐table payments in order to receive preferential medical treatment, when the questions mention words such as ‘illegal’ or ‘bribe’, respondents tend to be less tolerant of such activities. We find that, first, there is a basic willingness among Israeli citizens to use BMM. Second, despite this predilection, Israeli citizens are reluctant to articulate their willingness to engage in such illegal activities. This reluctance implies the existence of a moral barrier among the population as far as identifying themselves with illegal behaviour is concerned. We may infer the existence of a gap between declared attitudes and behaviour. Third, the fact that people's willingness to engage in BMM is greater than their willingness to adopt black‐market strategies in other areas signifies the special nature of health care. Finally, by connecting the phenomenon of BMM to public opinion regarding the welfare state, we point to a possible gap between normative attitudes and preferences produced by structural conditions.     

The Higher Education White Paper: The Good,the Bad,the Unspeakable – and the Next White Paper1

This article argues that reforms of higher education finance for undergraduates in England introduced by the Blair government in 2006 provided a progressive strategy for achieving the central objectives of higher education of quality (better), access (wider) and size (larger). Reforms in 2012 are a not a strategy but a collection of ad hoc arrangements. They include the good (a higher fees cap, a higher interest rate on student loans, better information and improved support for part‐time study), the bad (abolishing most taxpayer support for teaching in the arts and humanities and the social sciences, and raising excessively the threshold at which loan repayments start) and the unspeakable (abolishing Education Maintenance Allowances and AimHigher). The reforms are fiscally costly and hence perpetuate the central problem of capped student numbers, and will not stand the test of time. The concluding section outlines the next White Paper.     

Islamisation and activism of a Muslim NGO in Pakistan: Jama'at‐ud‐Da'wa as a case study

This paper locates the study of Jamat‐ud‐Da'wa (JUD) within the context of global political developments. Premised on the nexus between the local and the global developments, it discusses how changes in the domestic or international arena shaped the policies of JUD after 9/11. It argues that, as a successor to the Lashker‐e‐Toiba in Pakistan, the JUD has been active in the social welfare space. It has moved into roles that reside in the domain of the state's responsibility but have passed to the private sector due to the state's failure to meet the needs of its citizens, including the provision of education and relief and rescue efforts after natural disasters. Though not categorically identified as being part of the jihadi agenda, this activism increases the appeal of the JUD among Pakistani citizens, with a possibility of increasing their declared and/or active support for JUD's views on Pakistan's foreign policy.     

Job satisfaction and ‘welfare‐to‐work‘: is any job a good job for Australian single mothers?

This exploratory study sought to assess the job satisfaction of employed Australian single mothers who had mandatory employment participation requirements. In particular, we sought to identify the characteristics of the job and the individual that were closely associated with participant's job satisfaction. Self‐report data on job satisfaction, employment characteristics and parenting stress were collected from 155 employed single mothers. Participant job satisfaction was compared to female Australian population norms and linear regression analyses determined the job‐related and individual predictors of single mothers' job satisfaction. Findings from this exploratory study revealed that single mothers involved in a mandatory welfare‐to‐work program experienced significantly lower job satisfaction than the Australian female population. The individual variable, parental distress, negatively predicted each of the six job satisfaction domains while being employed on a casual basis was inversely associated with three domains (job security, work hours and overall job satisfaction). The Australian government purported that making the transition from welfare to work would improve wellbeing for program participants, under the assumption that ‘any job's a good job‘. However, the relatively low levels of job satisfaction experienced by single mothers in the current study provide little support for this assumption.     

Sustainable social work: Modelling knowledge production,transfer, and evidence‐based practice

Gray M, Schubert L. Sustainable social work: modelling knowledge production, transfer, and evidence‐based social work This article is a first attempt to present a model of knowledge production and transfer in social work, drawing on the expanding literature on knowledge production. It highlights features of knowledge production in social work, such as the diverse contexts in which knowledge is developed and applied. It argues that knowledge production by itself is not enough. Equally important is knowledge transfer and implementation. The literature on knowledge production highlights problems with the implementation of actually existing knowledge and the potential resistance to this implementation as highly important issues for social work research. It leads to a greater awareness of the context in which knowledge is produced and applied and creates a bridge between traditional informal and tacit ways of knowing in social work and the demands of evidence‐based practice.