Why Write Statistical Software? The Case of Robust Statistical Methods

Robust statistical methods are designed to work well when classical assumptions, typically normality and/or the lack of outliers, are violated. Almost everyone agrees on the value of robust statistical procedures. Nonetheless, after more than 40 years and thousands of papers, few robust methods were available in standard statistical software packages until very recently. This paper argues that one of the primary reasons for the lack of robust statistical methods in standard statistical software packages is the fact that few developers of statistical methods are willing to write user-friendly and readable software for the methods they develop, regardless of the usefulness of the method. Recent changes in academic statistics make it highly desirable for all developers of statistical methods to provide usable code for their statistical methods.

Injecting Successful Charter School Strategies into Traditional Public Schools: A Field Experiment in Houston

We implemented five strategies gleaned from practices in achievement-increasing charter schools – increased instructional time, a more rigorous approach to building human capital of teachers and administrators, high-dosage tutoring, frequent use of data to inform instruction, and a culture of high expectations – in twenty of the lowest performing schools in Houston, Texas. We show that the average impact of these changes on student achievement is 0.206 standard deviations in math and 0.043 standard deviations in reading, per year, which is comparable to reported impacts of attending high-performing charter schools. This suggests that the best practices of charter schools may be general lessons about the education production function.

Implementing ERP systems - organisational implications

Success of Enterprise Resource Planning (ERP) systems depend on rigorous and disciplined approach to planning and implementation. This article presents a selection and implementation methodology that has been applied to three similar companies and highlights a wide variation in outcome. The underlying reasons for the variations in success can be specifically attributed to organisational personalities and culture. Analysis of these case studies provides key lessons and concludes by summarising these lessons in a cause and effect diagram

Why Write Statistical Software? The Case of Robust Statistical Methods

Robust statistical methods are designed to work well when classical assumptions, typically normality and/or the lack of outliers, are violated. Almost everyone agrees on the value of robust statistical procedures. Nonetheless, after more than 40 years and thousands of papers, few robust methods were available in standard statistical software packages until very recently. This paper argues that one of the primary reasons for the lack of robust statistical methods in standard statistical software packages is the fact that few developers of statistical methods are willing to write user-friendly and readable software for the methods they develop, regardless of the usefulness of the method. Recent changes in academic statistics make it highly desirable for all developers of statistical methods to provide usable code for their statistical methods

Exploring internal child sex trafficking networks using social network analysis

This article explores the potential of social network analysis as a tool in supporting the investigation of internal child sex trafficking in the UK. In doing so, it uses only data, software, and training already available to UK police. Data from two major operations are analysed using in-built centrality metrics, designed to measure a network’s overarching structural properties and identify particularly powerful individuals. This work addresses victim networks alongside offender networks. The insights generated by SNA inform ideas for targeted interventions based on the principles of Situational Crime Prevention. These harm-reduction initiatives go beyond traditional enforcement to cover prevention, disruption, prosecution, etc. This article ends by discussing how SNA can be applied and further developed by frontline policing, strategic policing, prosecution, and policy and research

Ethical Issues in Engineering Models: Personal Reflections

I start this contribution with an overview of my personal involvement—as an Operations Research consultant—in several engineering case-studies that may raise ethical questions; these case studies employ simulation models. Next, I present an overview of the recent literature on ethical issues in modeling, focusing on the validation of the model’s assumptions; the decisive role of these assumptions leads to the quest for robust models. Actually, models are meant to solve practical problems; these problems may have ethical implications for the various stakeholders; namely, modelers, clients, and the public at large. Finally, I briefly discuss whistle blowing.ethics;code of conduct;stakeholders;validity;risk analysis;simulation;operations research

Reevaluating Adversarial Examples in Natural Language

State-of-the-art attacks on NLP models lack a shared definition of a what constitutes a successful attack. We distill ideas from past work into a unified framework: a successful natural language adversarial example is a perturbation that fools the model and follows some linguistic constraints. We then analyze the outputs of two state-of-the-art synonym substitution attacks. We find that their perturbations often do not preserve semantics, and 38% introduce grammatical errors. Human surveys reveal that to successfully preserve semantics, we need to significantly increase the minimum cosine similarities between the embeddings of swapped words and between the sentence encodings of original and perturbed sentences.With constraints adjusted to better preserve semantics and grammaticality, the attack success rate drops by over 70 percentage points.Comment: 15 pages; 9 Tables; 5 Figure

Testing a model of antecedents and consequences of defensive pessimism and self-handicapping in school physical education

There has been very limited research on the use of self-worth protection strategies in the achievement context of school physical education (PE). Thus, this study aimed to examine some antecedents and consequences of defensive pessimism and self-handicapping. The sample comprised 534 (females n = 275; males n = 259) British pupils recruited from two schools who responded to established questionnaires. Results of structural equation modelling analysis indicated that self-handicapping and defensive pessimism were positively predicted by fear of failure and negatively predicted by competence valuation. In addition, defensive pessimism was negatively predicted by physical self-concept. In turn, defensive pessimism negatively predicted enjoyment in PE and intentions to participate in future optional PE programs. Self-handicapping did not predict enjoyment or intentions. Results from multi-sample structural equation modelling showed the specified model to be largely invariant across males and females. The findings indicate that although both strategies aim to protect one’s self-worth, some of their antecedents and consequences in PE may differ

Cleveland Schools That Are Making a Difference

Profiles thirteen Cleveland schools -- a cross section of traditional public, private, parochial, and charter schools, where the majority of students are economically disadvantaged -- that have demonstrated progress in student achievement gains

Foodservice in hospital: development of a theoretical model for patient experience and satisfaction using one hospital in the UK National Health Service as a case study

Hospital foodservice does not operate in isolation but requires the cooperation and integration of several disciplines to provide the ultimate patient experience. The objective of this research was to explore the antecedents to patient satisfaction and experience, including the service element. Accordingly, focus groups were conducted with doctors (n = 4), nurses (n = 5), ward hostesses (n = 3) and patients together with their visitors (n = 10), while open-ended interviews were conducted with the foodservice manager, facilities manager, chief dietitian, orthopaedic ward dietitian and chief pharmacist. Themes centred on ‘patients’, ‘foodservice’ and ‘mealtimes’, and results show that food qualities, particularly temperature and texture, are important factors impinging on patient satisfaction, and the trolley system of delivery is an acceptable style of service. Service predisposition demonstrates little relevance to patient satisfaction towards overall meal enjoyment. A theoretical model has been developed that identifies hospital foodservice in a cyclic relationship with the community primary healthcare team