Regression Analysis of Multivariate Fractional Data

The present article discusses alternative regression models and estimation methods for dealing with multivariate fractional response variables. Both conditional mean models, estimable by quasi-maximum likelihood, and fully parametric models (Dirichlet and Dirichlet-multinomial), estimable by maximum likelihood, are considered. A new parameterization is proposed for the parametric models, which accommodates the most common specifications for the conditional mean (e.g., multinomial logit, nested logit, random parameters logit, dogit). The text also discusses at some length the specification analysis of fractional regression models, proposing several tests that can be performed through artificial regressions. Finally, an extensive Monte Carlo study evaluates the finite sample properties of most of the estimators and tests considered.     

Towards Common Ground and Trading Zones in Management Research and Practice

The purpose and nature of management scholarship is contested, evidenced by debates about the ‘academic–practitioner divide’ and attendant remedies for addressing it, including mode 2 and mode 3 research, engaged scholarship, evidence‐based management and design science. In this paper the authors argue that, without a culture of dialogical encounter, management scholarship will never be able to emerge from its adolescence, and management will not develop into the profession that it should and can become. The central proposition is that the highly fragmented landscape of management (practice and scholarship) lacks sufficient capability for dialogue among the plurality of actors situated across that landscape. Developing the dialogical capability ultimately required to break this fundamental impasse demands, first, a shared sense of purpose and responsibility (akin to the Hippocratic Oath in medicine) and, second, institutional entrepreneurship to establish more and better ‘trading zones’. Drawing on the philosophy of pragmatism, the authors further this endeavour by identifying and proposing key elements of a statement of shared purpose and responsibility. Finally, they explore the nature and characteristics of successful trading zones, highlighting particular examples that have already been created in management studies.     

Motivational factors and physician advice for physical activity in older urban adults

This study aimed to ascertain by means of a new scale older adults' motives for engaging in physical activity, in a probability and representative sample of an older urban population. The sample size was 630 older adults, ranging from 65 to 94 years in age, randomly selected using multistage sampling. The participants completed a 17-item questionnaire, as well as answering questions on demographic variables, type of demand for physical activity, and physician's recommendation. A principal-component analysis was performed. The relationships among the four factors (physical health, social relationships, competence, and physician's advice) show a clearly motivational structure. Significant relationships have also been found between physician's recommendation and type of demand. The findings suggest that programs promoting physical activity in older adults should have different characteristics from those aimed at general adult populations.     

Cooperative learning: we can also do it without task structure

The present study focuses on the use of a cooperative methodology with university students during the last year of their degree programme. The task structure could be freely chosen, and there were no restraints on group decisions to deal with the classroom work. All the elements of cooperation were based on a reward structure. The results show that internal group cohesion can be achieved through an inter‐group competitive reward system and positive interdependence can be reached with an extreme cooperative reward structure, grounded on individual assessments of the students. The results also point to the importance of a reward structure, based on grades, when using a cooperative methodology in the university classroom.

Este estudio supone la utilización de una metodología cooperativa con alumnos universitarios en el último curso de la carrera. La estructura de tarea es siempre libre y no hay ninguna restricción a las decisiones del grupo para abordar el trabajo de aula. Todos los elementos de la cooperación se abordan desde la estructura de recompensa: la cohesión interna de los grupos se consigue mediante un sistema de recompensa competitiva intergrupal y la interdependencia positiva se logra mediante una estructura de recompensa cooperativa extrema, basada en las evaluaciones individuales de los alumnos. Los resultados demuestran la importancia que tiene una estructura de recompensa, basada en las calificaciones, para la aplicación de una metodología cooperativa al aula universitaria.