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7 April 2009

Special Lecture by David Firth on Quasivariances

We are pleased to announce a special presentation that should be of interest. David Firth, Professor of Statistics at the University of Warwick, will present on Quasi Variances this *Thursday* from 12-2 pm in room K-354 in CGIS-Knafel (1737 Cambridge St, the usual meeting place for the applied statistics workshop). Professor Firth provided the following abstract for his presentation:

The notion of quasi variances, as a device for both simplifying and enhancing the presentation of additive categorical-predictor effects in statistical models, was developed in Firth and de Menezes (Biometrika, 2004, 65-80). The approach generalizes the earlier idea of "floating absolute risk" (Easton et al., Statistics in Medicine, 1991), which has become rather controversial in epidemiology. In this talk I will outline and exemplify the method, and discuss its extension to some other contexts such as parameters that may be arbitrarily scaled and/or rotated.

A bit of background on Professor Firth. He is Professor of Statistics at the University of Warwick. He specializes in statistical theory and methods, and has a particular interest in generalized linear models---especially as applied to the social sciences. He has published extensively in the discipline's major journals of record, such as JRSS and Biometrika, and has written several packages for the R language and environment. He has made several significant contributions to the field, and is well known as the inventor of bias-reduced logistic regression (also known as 'Firthit').

He is at IQSS as a Distinguished Visiting Fellow (April 7--17), and will be spending part of his time here working with Arthur Spirling on models of momentum for contest data.

We hope everyone will be able to attend

Posted by Justin Grimmer at 5:52 PM

Sequeira on the Efficiency Cost of Corruption

The workshop will meet tomorrow, when Sandra Sequeira, a PhD candidate in public policy, will present her work on the efficiency cost of corruption, work that is joint with Simeon Djankov. Sandra provided the following abstract for her talk:

This paper estimates the efficiency cost of corruption. We generate an original dataset on bribe payments at ports in Southern Africa that allows us to take an unusually close look into the black box of corruption, observing how bureaucrats set bribes and measuring their economic costs on firms and on the broader economy. We find that bribes are product-specific, frequent and substantial. Bribes can represent up to a 14\% increase in total shipping costs for a standard 20ft container and a 600\% increase in the monthly salary of a port official. Bribes are paid primarily to evade tariffs, protect cargo on the docks and avoid costly storage. We further identify three systemic effects associated with this type of corruption: a ``diversion effect" where firms go the long way around to avoid the most corrupt port; a ``revenue effect" as bribes reduce overall tariff revenue; and a ``congestion effect" as the re-routing of firms increases congestion and transport costs by causing imbalanced cargo flows in the transport network. The evidence supports the theory that bribe payments at ports represent a significant distortionary tax on trade, as opposed to just a transfer between shippers and port officials that greases slow-moving clearing queues.

The Applied Statistics Workshop meets each Wednesday at 12 noon in K-354 CGIS-Knafel (1737 Cambridge St). The workshop begins with a light lunch and presentations usually start around 1215 and last until about 130 pm.

Posted by Justin Grimmer at 5:46 PM