Efficient minimum distance estimation with multiple rates of convergence

This paper extends the asymptotic theory of GMM inference to allow sample counterparts of the estimating equations to converge at (multiple) rates, different from the usual square-root of the sample size. In this setting, we provide consistent estimation of the structural parameters. In addition, we define a convenient rotation in the parameter space (or reparametrization) to disentangle the different rates of convergence. More precisely, we identify special linear combinations of the structural parameters associated with a specific rate of convergence. Finally, we demonstrate the validity of usual inference procedures, like the overidentification test and Wald test, with standard formulas. It is important to stress that both estimation and testing work without requiring the knowledge of the various rates. However, the assessment of these rates is crucial for (asymptotic) power considerations.Possible applications include econometric problems with two dimensions of asymptotics, due to trimming, tail estimation, infill asymptotic, social interactions, kernel smoothing or any kind of regularization.     

Public school availability for two-year olds and mothers' labour supply

French children start public school either the year they turn two or the year they turn three. We evaluate the impact of this unique schooling policy on maternal labour supply. Using a Regression–Discontinuity design, we show that early school availability has a significant employment effect on lone mothers, but no effect on two-parent families. Also we show that the effect grows larger as the child grows older and as the family loses eligibility for child benefits. Finally, we provide some new evidence that school enrolment at the age of two has no adverse effect on children's subsequent educational outcomes.     

Bayesian inference for periodic regime-switching models

We present a general class of nonlinear time-series Markov regime-switching models for seasonal data which may exhibit periodic features in the hidden Markov process as well as in the laws of motion in each of the regimes. This class of models allows for non-trivial dependencies between seasonal, cyclical and long-term patterns in the data. To overcome the computational burden we adopt a Bayesian approach to estimation and inference. This paper contains two empirical examples as illustration, one uses housing starts data while the other employs US post-Second World War industrial production. © 1998 John Wiley & Sons, Ltd.     

Open Variety Rights: Rethinking the Commodification of Plants

Open Variety Rights refer to the removal of the conditions attached to the usage of plants in agriculture, and to an analogy with open licensing in informatics that is notably different from the one that is taking shape at the intersection of the life sciences and informatics. This paper argues for the open licensing of plants as part of a response to the commodification of DNA; rather than a singular focus on farming or source code, this implies an analogy that aims at the removal of restrictions, whether as seeds, biodiversity, genetic sequences or DNA in informatics formats. First, the commodification of plants will be conceptualized. Second, the proposal for open licensing for varieties of crops will be discussed. Third, examples of the introduction of open licensing in the life sciences will be examined in relation to the potential to reformulate the definition of ‘openness’ to support those who wish to live and work with plants on their own terms.     

Causality effects in return volatility measures with random times

We provide a structural approach to identify instantaneous causality effects between durations and stock price volatility. So far, in the literature, instantaneous causality effects have either been excluded or cannot be identified separately from Granger type causality effects. By giving explicit moment conditions for observed returns over (random) duration intervals, we are able to identify an instantaneous causality effect. The documented causality effect has significant impact on inference for tick-by-tick data. We find that instantaneous volatility forecasts for, e.g., IBM stock returns must be decreased by as much as 40% when not having seen the next quote change before its (conditionally) median time. Also, instantaneous volatilities are found to be much higher than indicated by standard volatility assessment procedures using tick-by-tick data. For IBM, a naive assessment of spot volatility based on observed returns between quote changes would only account for 60% of the actual volatility. For less liquidly traded stocks at NYSE this effect is even stronger.     

Becoming an evidence‐based HR practitioner

Evidence‐based HR (EBHR) is a decision‐making process combining critical thinking with use of the best available scientific evidence and business information. We describe how to get started as an evidence‐based HR practitioner. Actively managing professional decisions is a key aspect of EBHR. Doing so involves making decisions, especially consequential or recurring ones, using practices supported by high‐quality research. We present a step‐by‐step set of approaches to becoming an evidence‐based HR practitioner: from getting started, through everyday practices and continuous learning to integrating EBHR into your organisation. In offering guidance for evidence‐based practice, this article underscores the connection between effective practice and organisational research.     

Successful programs wanted: Exploring the impact of alignment

Alignment between formulation and implementation of business strategy can be important for achieving successful programs. The authors have explored the development of a program management alignment theory. Statistical testing showed that interaction between the study model variables was found to be multidimensional, complex, and subtle in influence. Thus, the authors conclude that programs have both deliberate and emergent strategies requiring design and management to be organized as complex adaptive systems. Program life‐cycle phases of design and transition were often formed from an unclear and confusing strategic picture at the outset, which can make those phases difficult to control. Learning was established as an underlying challenge. The study model demonstrated continuous alignment as an essential attribute contributing toward successful delivery. This requires program design and structure to adopt an adaptive posture.     

Trust and corruption revisited: how and why trust and corruption shape each other

Graeff and Svendsen argue that low trust leads to corruption but corruption does not lower trust. I challenge this argument as well as their critique of Uslaner. I present evidence to show that there is a reciprocal relationship between trust and corruption.     

Real-life cost of vitamin K antagonist treatment in patients with non-valvular atrial fibrillation in France in 2013

Aims: Data highlighting the cost drivers for non-valvular atrial fibrillation (NVAF) patients in terms of vitamin K antagonist (VKA) treatment and monitoring are lacking in France. This study aimed to evaluate the real-life daily cost of VKA treatment in 2013, in French patients suffering from NVAF.

Methods: This longitudinal observational study was performed using the EGB (Echantillon Généraliste des Bénéficiaires) database, a random sample of the French national insurance (NHI) database, which covers 80% of the population. All adult patients whose first NVAF anticoagulant treatment in 2013 was a VKA were analyzed. Costs were calculated for the duration of follow-up and then divided by the number of days of therapy. The analysis was performed both from the French NHI perspective (amount reimbursed by the NHI) and from a collective perspective.

Results: In this study, 3,254 NVAF patients treated with VKA in 2013 were included, and this sample comprised 52.6% males. The mean daily cost of VKA treatment was €1.13 (±1.18) according to the collective perspective (89.4% of this cost was associated to INR measurement) and €1.05 (±1.16) according to the NHI perspective.

Limitations: As diagnoses associated with procedures are not available in the EGB database, proxies were used, and an algorithm was created to define the AF population.

Conclusions: This analysis is the first to consider an exhaustive spectrum of the costs of VKA treatment in France using EGB data. VKA medication requires exhaustive follow-up, and, thus, associated costs are important. The results of the present study confirmed this close follow-up for VKA patients, making the cost of treatment by VKA nearly 10-times more expensive than the cost of medication itself.