gov3009-l October 2007

gov3009-l@lists.fas.harvard.edu

1 participants
5 discussions

Andrew C. Thomas on "Symmetry and Competition in State Legislative Election Systems".

by Justin Grimmer

Dear Applied Statistics Community, This week we present Andrew C. Thomas, G-4 Department of Statistics, who will present his work on "Symmetry and Competition in State Legislative Election Systems". Andrew has provided the following abstract for his presentation: Drawing of legislative districts has historically been conducted by the legislators themselves; recently, some states have appointed redistricting commissions, the members of which cannot run for seats in the legislature for a period afterwards. I demonstrate that current methods, in particular the Gelman-King model and the JudgeIt R package, can easily diagnose the state of an electoral map given previous electoral conditions. In particular, competition increases in states with commissions, but the impact on symmetry is as yet unclear. I conclude with a discussion on techniques to improve the resolution and measurement of electoral symmetry within states. Please join us this Wednesday at 12noon for the presentation and a light lunch. We hold the workshop in Room N-354 of CGIS-Knafel (1737 Cambridge St). I hope that you will be able to attend Cheers, Justin Grimmer

16 years, 5 months

James Stock on ‘Forecasting in Dynamic Factor Models’

by Justin Grimmer

The Applied Statistics Workshop is proud to present James Stock, Chair of the Economics Department, as he presents, "Forecasting in Dynamic Factor Models Subject to Structural Instability". James has provided the following abstract: Dynamic factor models (DFMs) express the comovements of time series at leads and lags in terms of a small number of latent factors. In macroeconomic applications, the latent factors can be thought of as theoretical constructs (income) that are linked to specific measurements (GDP). The large body of work on DFMs in macroeconomics assumes a stable structure. This paper develops time-varying DFMs and uses implications of time-varying DFMS to shed light on some ongoing macro puzzles such as the Great Moderation and the breakdown of the backward-looking Phillips curve. The workshop will meet at 12-noon in room N-354, CGIS-Knafel. And a light lunch will be served. Hope you can make it, Justin Grimmer

16 years, 6 months

Damon Centola on 'Diffusion in Social Networks'

by Justin Grimmer

Dear Applied Statistics Community, The applied statistics workshop is back for another exciting installment. This week we have Damon Centola, RWJ Scholar, Harvard University to present on 'Diffusion in Social Networks: New Theory and Experiments' . Damon provided the following abstract for his talk: The strength of weak ties is that they tend to be long – they connect socially distant locations. Research on "small worlds" shows that these long ties can dramatically reduce the "degrees of separation" of a social network, thereby allowing ideas and behaviors to rapidly diffuse. However, I show that the opposite can also be true. Increasing the frequency of long ties in a clustered social network can also inhibit the diffusion of collective behavior across a population. For health related behaviors that require strong social reinforcement, such as dieting, exercising, smoking, or even condom use, successful diffusion may depend primarily on the width of bridges between otherwise distant locations, not just their length. I present formal and computational results that demonstrate these findings, and then propose an experimental design for empirically testing the effects of social network topology on the diffusion of health behavior. The workshop is held on Wednesday at 12 noon in room N 354, CGIS Knafel (1737 Cambridge St). And a light lunch will be served. If you have any questions or concerns please don't hesistate to contact me, Best, Justin Grimmer

16 years, 6 months

Fernanda B. Viegas presenting 'From Wikipedia to Visualization and Back'

by Justin Grimmer

Dear Applied Statistics Community, Please join us for this week's installment of the Applied Statistics workshop, where Fernanda Viegas will be presenting her talk entitled, "From Wikipedia to Visualization and Back'. Fernanda provided the following abstract for her talk: This talk will be a tour of our recent visualization work, starting with a case study of how a new data visualization technique uncovered dramatic dynamics in Wikipedia. The technique sheds light on the mix of dedication, vandalism, and obsession that underlies the online encyclopedia. We discuss the reaction of the Wikipedia community to this visualization, and how it led to a recent ambitious project to make data visualization technology available to everyone. This project, Many Eyes, is a web site where people may upload their own data, create interactive visualizations, and carry on conversations. The goal is to foster a social style of data analysis in which visualizations serve not only as a discovery tool for individuals but also as a means to spur discussion and collaboration. Fernanda also provided links to the following papers, http://alumni.media.mit.edu/~fviegas/papers/history_flow.pdf<http://alumni.media.mit.edu/%7Efviegas/papers/history_flow.pdf> http://www.research.ibm.com/visual/papers/viegasinfovis07.pdf And to a website based upon her recent work in data visualization Link to Many Eyes site: www.many-eyes.com As always, the workshop meets at 12 noon on Wednesday, in room N-354 CGIS-Knafel. A light lunch will be provided Best, Justin Grimmer

16 years, 6 months

Thomas Cook at the Applied Statistics Workshop

by Justin Grimmer

The Applied Statistics Workshop presents another installment this week with Thomas Cook, Department of Sociology, Northwestern University presenting a talk entitled, "When the causal estimates from randomized experiments and non-experiments coincide: Empirical findings from the within-study comparison literature." <http://people.fas.harvard.edu/%7Ejgrimmer/Cook.doc>Here is an excerpt from the paper: The present paper has several purposes. It seeks to up-date the literature since Glazerman et al. (2003) and Bloom et al. (2005) and to move it beyond its near exclusive focus on job training. We have examined the job training studies, and find nothing to challenge the past conclusions described above. However, the more recent studies allow us to broach three questions that are more finely differentiated than whether experiments and non-experiments produce comparable findings: 1. Do experiments and RDD studies produce comparable effect sizes? We have found three examples attempting this comparison. 2. Do comparable effect sizes result when the non-experiment depends on selecting one or more intact comparison groups that are deliberately matched on pretest measures of the posttest outcome, as recommended in Cook & Campbell (1979)? Thus, in a non-experiment with schools as the unit of assignment, intervention schools are carefully matched with intact non-intervention schools in the hope that the average treatment and comparison schools will not differ on pretest achievement, let us say, though they may differ on unobservables. We have found three studies with this focus. 3. Do experiments and non-experiments produce comparable effect sizes when the intervention and comparison units do differ at pretest and so statistical adjustments or individual matches are constructed to control for this demonstrated non-equivalence? This question has dominated the literature to date, and we found six studies outside of job training that asked this question We will meet at 12 noon in CGIS-Knafel N354 and the talk will begin at 1215pm. And of course a delicious, free lunch will be provided. Please email me with any questions/concerns/suggestions for the workshop Justin Grimmer

16 years, 6 months

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gov3009-l October 2007