ADE-4: a multivariate analysis and graphical display software

We present ADE-4, a multivariate analysis and graphical display software. Multivariate analysis methods available in ADE-4 include usual one-table methods like principal component analysis and correspondence analysis, spatial data analysis methods (using a total variance decomposition into local and global components, analogous to Moran and Geary indices), discriminant analysis and within/between groups analyses, many linear regression methods including lowess and polynomial regression, multiple and PLS (partial least squares) regression and orthogonal regression (principal component regression), projection methods like principal component analysis on instrumental variables, canonical correspondence analysis and many other variants, coinertia analysis and the RLQ method, and several three-way table (k-table) analysis methods. Graphical display techniques include an automatic collection of elementary graphics corresponding to groups of rows or to columns in the data table, thus providing a very efficient way for automatic k-table graphics and geographical mapping options. A dynamic graphic module allows interactive operations like searching, zooming, selection of points, and display of data values on factor maps. The user interface is simple and homogeneous among all the programs; this contributes to making the use of ADE-4 very easy for non- specialists in statistics, data analysis or computer science.     

Does product complexity matter for competition in experimental retail markets?

We describe a first experiment on whether product complexity affects competition and consumers in retail markets. We are unable to detect a significant effect of product complexity on prices, except insofar as the demand elasticity for complex products is higher. However, there is qualified evidence that complex products have the potential to induce consumers to buy more than they would otherwise. In this sense, consumer exploitability in quantities cannot be ruled out. We also find evidence for shaping effects: consumers’ preferences are shaped by past experience with prices, and firms may in principle exploit this to sell more.     

Activation and social inclusion: challenges and possibilities

The last two decades have seen an increasing focus on the activation of individuals receiving welfare benefits. This has entailed an attempt to transform employment assistance and social security systems to make them more employment‐friendly through the development of explicit linkages between social protection policies, labour market participation and labour market programs. At the same time there has been a growing interest in the concept of social inclusion, and social inclusion has been a commonly stated goal of activation programs. However, despite some synergies between these two approaches, in other respects it is not clear that they are always compatible. This paper explores the extent to which activation programs are central to the social inclusion approach and the similarities and differences between these approaches. It then briefly examines the evidence regarding the ability of activation programs to enhance social inclusion.     

Differentiated leader–member exchange,justice climate,and performance: Main and interactive effects

Leaders form different quality leader–member exchange (LMX) relationships with their subordinates. This variable treatment termed LMX differentiation can have negative effects on individuals' behavior and attitudes. In this study, we examined the cross-level main effect of justice climate on task performance and the moderating role of justice climate on the relationship between LMX differentiation and task performance. We tested these two hypotheses using a field study of 90 subordinates nested under 27 supervisors. Procedural justice climate, not distributive justice climate, was found to positively influence subordinate task performance. Further, distributive justice climate, not procedural justice climate, was found to moderate the LMX differentiation–task performance relationship; such that the relationship was positive when distributive justice climate was high and negative when distributive justice climate was low. Findings and future directions are discussed.     

Effects of Leadership Style,Creativity Technique and Personal Initiative on Employee Creativity

Transformational leadership is assumed to enhance employees' creativity. However, results of meta‐analytic research on the relations between transformational leadership and creativity have fallen short of expectations. The authors argue that, besides leadership style, the creativity technique that a leader employs is an important means of stimulating employees' creativity. In addition, it is assumed that leadership styles and creativity techniques may have different effects, depending on the measure of creativity output (quantitative vs qualitative). Therefore, in an experimental setting, the effects of different creativity techniques (provocation technique vs brainwriting) and leadership styles (transformational vs transactional) on both quantitative and qualitative creativity were examined. Results showed that transformational leadership and provocation technique led to higher levels of qualitative creativity than transactional leadership and brainwriting, respectively. Conversely, transactional leadership and brainwriting were more effective for quantitative creativity. The additional benefit of the provocation technique in qualitative creativity was found to be higher in the transactional leadership condition than in the transformational leadership condition. Moreover, personal initiative made a significant and independent contribution to both qualitative and quantitative creativity. Implications for practice and future research are discussed.     

Racial capitalism and STEM education in Chicago Public Schools

ABSTRACT

This article analyzes the role of STEM initiatives designed by city and corporate elites in a large urban district and outlines an alternative, grassroots vision for (STEM) education and city schools. Within a neoliberal context of gentrification, displacement, disinvestment, and privatization, STEM schools have become strategic components of Chicago’s ‘portfolio district’ that serve the interests of racial capitalism in three ways. First, STEM schools provide a claim to fairness in the midst of racist school closures. Second, STEM high schools are a corporate strategy for racially stratified labor force preparation that restricts curriculum and reifies tracking. Third, curriculum restriction prioritizes corporate interests over students’ capacity to shape their communities and the world. The authors draw on the wisdom of Chicago communities who have led resistance against corporate education reform to critique Chicago STEM policy and point to critical mathematics and science education as part of a model for sustainable community schools.     

Robust Bayesian model selection for variable clustering with the Gaussian graphical model

Statistics and Computing - Variable clustering is important for explanatory analysis. However, only few dedicated methods for variable clustering with the Gaussian graphical model have been...     

Linear Increments with Non‐monotone Missing Data and Measurement Error

Linear increments (LI) are used to analyse repeated outcome data with missing values. Previously, two LI methods have been proposed, one allowing non‐monotone missingness but not independent measurement error and one allowing independent measurement error but only monotone missingness. In both, it was suggested that the expected increment could depend on current outcome. We show that LI can allow non‐monotone missingness and either independent measurement error of unknown variance or dependence of expected increment on current outcome but not both. A popular alternative to LI is a multivariate normal model ignoring the missingness pattern. This gives consistent estimation when data are normally distributed and missing at random (MAR). We clarify the relation between MAR and the assumptions of LI and show that for continuous outcomes multivariate normal estimators are also consistent under (non‐MAR and non‐normal) assumptions not much stronger than those of LI. Moreover, when missingness is non‐monotone, they are typically more efficient.