Practical Collapsed Stochastic Variational Inference for the HDP

Recent advances have made it feasible to apply the stochastic variational paradigm to a collapsed representation of latent Dirichlet allocation (LDA). While the stochastic variational paradigm has successfully been applied to an uncollapsed representation of the hierarchical Dirichlet process (HDP), no attempts to apply this type of inference in a collapsed setting of non-parametric topic modeling have been put forward so far. In this paper we explore such a collapsed stochastic variational Bayes inference for the HDP. The proposed online algorithm is easy to implement and accounts for the inference of hyper-parameters. First experiments show a promising improvement in predictive performance.Comment: NIPS Workshop; Topic Models: Computation, Application, and Evaluatio

Horizontal Inequalities and Violent Conflict. Côte d’Ivoire Country Paper

human development, aid, trade, security

Between fallacy and feasibility? Dealing with the risk of ecological fallacies in the quantitative study of protest mobilization and conflict

In recent years, the quantitative study of conflict has increasingly focused on small-scale and/or localized conflicts in the developing world. In this paper, we analyze and critically reflect upon a major methodological shortcoming of many studies in this field of research. We argue that by using group- or macro-level empirical data and modelling techniques, while at the same time theoretically underpinning observed empirical associations with individual-level mechanisms, many of these studies risk committing an ecological fallacy. The individual-level mechanism on which many studies rely concerns the presence of grievances which mobilize people to participate in contentious politics. This motivational approach was also present in early studies on protest mobilization in Western societies, which often relied on similar research designs. However, subsequent advances in this literature and the use of methods that were targeted more directly at the individual level uncovered that grievances alone cannot explain mobilization and that organizational capabilities and complex psychological mechanisms of belonging also form part of the puzzle. While drawing on conflict events as well as survey data from Africa, we demonstrate empirically that here, as well, inferring micro-level relations and dynamics from macro-level empirical models can lead to erroneous interpretations and inferences. Hence, we argue that to improve our understanding of conflict mobilization in the developing world, especially for conflicts with low levels of violence, it is necessary to substantially expand our methodological toolbox beyond macro-level analyses

Economic liberalization and constraints to development in sub-Saharan africa

This paper critically reviews the impact of globalization on Sub-Saharan Africa (SSA) since the early 1980s. The large gains expected from opening up to international economic forces have, to date, been limited, and there have been significant adverse consequences. FDI in SSA has been largely confined to resource, especially mineral, extraction, even as continuing capital flight has reduced financial resources available for productive investments. Premature trade liberalization has further undermined prospects for SSA economic development as productive capacities in many sectors are not sufficiently competitive to take advantage of any improvements in market access.Development, Agriculture, Africa, Trade liberalization, FDI, Bretton Woods Institutions

Macro Adjustment Policies and Horizontal Inequalities

While there has been a considerable amount of analysis on the impact of structural adjustment policies on poverty and inequality among individuals (or what we define here as vertical inequality - VI), there has been almost none into the impact of structural adjustment on inequality between culturally defined groups, or horizontal inequality (HI). Although relatively neglected in economic analysis, socio-economic HIs are important from a number of perspectives - they can have adverse effects on the wellbeing of members of the deprived groups, they can impede efficiency, they may make it very difficult to eradicate poverty, they lead to unfair and exclusionary societies, and they raise the risk of violent conflict. Hence it is important to analyse the impact of structural adjustment policies on HIs - which is the aim of this paper.