General linear processes in Hilbert spaces and prediction

We discuss a general definition of linear processes in Hilbert spaces that takes into account the outstanding role played by this model in prediction theory.     

Asymptotic variances for the multiplicative interaction model

When modelling two-way analysis of variance interactions by a multiplicative term-[Formula] asymptotic variances and covariances are derived for the parameters p, yi and Sj using maximum likelihood theory. The asymptotic framework is defined by a2/K where K is the number of observations per combination of the two factors and a2 the common variance of the eijk values. The results can be applied when K = 1. Two Monte Carlo studies were carried out to check the validity of the formulae for small values of 02/K and to assess their usefulness when replacing the unknown parameters by their estimations. The formulae fit well but the confidence regions produced are too narrow if the interaction term is small. The procedure is illustrated with two examples.     

Agreement Between Mothers and Fathers on the Identification of Infant Communicative Acts: Use of a Randomization Procedure

The extent to which mothers and fathers agree on what they identify as their infant's communicative acts was investigated. Nineteen infants (6 at 6 months, 7 at 9 months, and 6 at 12 months) and their parents participated. A randomization procedure controlled for the frequencies and durations of the communicative acts identified by the parents, and the procedure produced a distribution of 10,000 “chance” agreement values for each parent pair with which their observed level of agreement was compared. The results indicated that, generally, parents could identify their infant's communicative acts consistently, and that observed levels of agreement between parents were significantly higher than would be expected by chance. Differences between mothers and fathers on their identification of communicative acts are considered in terms of the emergence of the infant's intention to communicate.     

Toward a comprehensive ‘quality-of-life’ index

Any attempt to construct an overall measure of the quality-of-life (“QOL”) of a community, population group, or larger society must inevitably confront the critical obstacle posed by the absence of a common numéraire. The diverse elements that significantly affect the “QOL” of individuals and social groups are each subject, at least in principle, to some form of measurement, but no satisfactory method has yet been devised whereby these different measurements could be reduced to a single metric.The construct that is developed in this paper cannot claim to have overcome this fundamental problem; nor does it settle the equally basic difficulties relating to what specific indicators to include in the composite construct, and how to weigh their individual values. However, it illustrates one possible approach toward the development of a summary index value that provides some insight into both direction (“favorable” or “unfavorable”) and magnitude of observed year-to-year changes in a selected number of fairly representative socioeconomic indicators for which measures were available for the United States annually from 1969 to the present. The information provided by this index lacks explanatory power, but examination of the components of the observed changes in the index does yield some useful insight into the relative contribution of changes in different “areas of concern” to the overall changes observed in the “QOL” in the United States during the 1969–1985 period.     

The RSA (Revenu de solidarité active) and back‐to‐work incentives in France

Using an inventory of local and/or non‐statutory transfers (droits connexes) in 13 French towns and cities, the article first measures the gains from returning to work for recipients of national, statutory means‐tested benefits (Revenu minimum d'insertion— RMI, and Allocation parent isolé— API) by type of household before 2009. The reforms of national, statutory benefits carried out during the 2000s, especially those affecting the working tax credit (Prime pour l'emploi— PPE), failed to ensure that the recipients of means‐tested benefits always stood to gain financially from returning to work. The effects of the reforms were offset by the effects of other measures. The article then simulates the effects of the introduction of the Revenu de solidarité active (RSA) in place of the RMI in 2009, and takes into account the way that local and/or non‐statutory transfers are modified by increases in national, statutory transfers. We observe that the RSA eliminates the financial disincentives to returning to work for almost all localities and types of household. The article shows that the marginal tax rate of 38 per cent chosen by the government is very close to the upper limit compatible with a back‐to‐work incentive.     

The Inherently Contested Nature of Nongovernmental Accountability: The Case of HAP International

While the principled case for humanitarian accountability is relatively straightforward, the practice is demonstrably more complicated, necessitating constant negotiation among stakeholders. However, despite the wave of research into nongovernmental accountability, few empirical studies have grappled with the phenomenon’s inherently contested nature. This paper foregrounds tensions arising in the elaboration of nonprofit accountability. Its approach is informed by critical constructivist theory, an international relations approach attuned to social power, identity and exclusion, and conceptual contestation; its conclusions are supported by interview data with key stakeholders. Focusing on the Humanitarian Accountability Partnership (HAP) International, it finds that initial consensus on the desirability of beneficiary (downward) accountability quickly gave way to principled disagreements and operational difficulties. Specifically, the initiation stage of HAP was marked by two conflicts—a debate about enforcement and a turf war over control—culminating in rebranding and relocation. The implementation stage was characterized by tensions over certification and intra-organizational struggles over leadership. The contemporary practice of accountability is shown to be a contingent and contested social process, with humanitarian identity and practice ultimately at stake.

     

Semiparametric estimation in the normal variance-mean mixture model

In this paper we study the problem of statistical inference on the parameters of the semiparametric variance-mean mixtures. This class of mixtures has recently become rather popular in statistical and financial modelling. We design a semiparametric estimation procedure that first estimates the mean of the underlying normal distribution and then recovers non-parametrically the density of the corresponding mixing distribution. We illustrate the performance of our procedure on simulated and real data.     

On the versatility of Little’s Law in operations management: a review and classification using vignettes

Abstract

Despite Little’s Law being considered as one of the ‘laws’ of operations management, evidence of its application in an empirical context is diverse and diffuse. Hence, this paper aims to identify, classify and consolidate published empirical applications of Little’s Law in a systematic manner to better understand its versatility. This paper undertakes a systematic literature review of the databases of the five main publishers of operations management journals and snowball sampling for additional papers. A final sample of 128 empirical journal articles is identified and categorized. Tactical, medium-term decisions relating to capacity dynamics and operations re-engineering are the most popular categories. To give further insights into versatility, vignettes for each category are developed. The review and vignettes confirm Little’s Law as a highly relevant paradigm to operations management decisions due to its empirical versatility across levels, sectors and time domains. The paper suggests four factors to underline the empirical versatility of Little’s Law in operations management: applicability, utility, simplicity and visibility.