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    ESP and Bayes at the Times

    You say you wanted an update on that ESP paper where a professor of psychology “time-reversed” some classic experiments? The New York Times has you covered. Want to see more discussion of null hypotheses and Bayesian analysis in the NYT? Also covered:

    Many statisticians say that conventional social-science techniques for analyzing data make an assumption that is disingenuous and ultimately self-deceiving: that researchers know nothing about the probability of the so-...

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    Estimating the Causal Effect of Incumbency

    Jens Hainmueller

    Since the early seventies, political scientists have been interested in the causal effects of incumbency, i.e. the electoral gain to being the incumbent in a district, relative to not being the incumbent. Unfortunately, these two potential outcomes are never observed simultaneously. Even worse, the inferential problem is compounded by selection on unobservables. Estimates are vulnerable to hidden bias because there probably is a lot of unobserved stuff that’s correlated with both incumbency and electoral success (such as candidate quality, etc.)...

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    Estimation of the Stereotyped Ordered Regression Model

    While reading Xiaogang Wu and Donald Treiman's paper entitled "Inequality and Equality under Chinese Socialism: The Hukou System and Intergenerational Occupational Mobility" in American Journal of Sociology (2007, 113: 415-445) , I was directed to a technical paper written by John Hendrickx (2000), describing how to use "mclgen" and "mclest" in Stata to estimate the Stereotyped Ordered Regression Model (SOR) in social mobility studies.

    SOR is similar to conventional ordinal Logit models, but with a scaling metric to scale the effects of the independent variables on the...

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    Everything about causal inference in 40 pages

    Judea Pearl describes his new article Causal inference in statistics: An Overview as "a recent submission to Statistics Survey which condenses everything I know about causality in only 40 pages." That seemed like a bold claim, but after reading it I'm sold. I don't come from Pearl's "camp" per se, but I found this a really impressive overview of his approach to causation. His overtures to folks like me who use the potential outcomes framework were much appreciated, although it...

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    Evolutionary Thoughts on Evolutionary Monte Carlo

    Gopi Goswami

    Thanks a lot to Mike Kellerman for inviting me over for the talk on Oct 26, 05 at the IQSS (see here for details). I really enjoyed giving the talk and getting interesting comments and questions from the audience. In particular, Prof. Donald Rubin, Prof. Gary King and others made important contributions which I really appreciate. Prof. Kevin Quinn gave me some excellent suggestions on how...

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    Expansion of Economics

    John Friedman

    In my last post, I wrote about the methodological identity of economics and some of the corresponding advantages. But perhaps the greatest benefit to economists from this definition of the discipline is the great range of subjects on which one can work.

    There are, of course, areas of inquiry traditionally dominated by economists – monetary policy, or the profit-maximizing activities of companies, to name a few – and most people connect economics, as a...

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    Experimental prudence in political science (Part I)

    Mike Kellermann

    We've talked a fair bit on the blog about the use of experimental data to make causal inferences. While the inferential benefits of experimental research are clear, experiments raise prudential questions that we rarely face in observational research; they require "manipulation" in more than one sense of that word. As someone who is an interested observer of the experimental literature rather than an active participant, I wonder how well the institutional mechanisms for oversight have adapted to field experimentation in the social sciences in...

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    Experts and Trials I: Game Theory

    John Friedman

    No sooner had the recent posts on this blog by Jim Greiner about the use of statistics and expert witnesses in trials
    (see here and here, as well as yesterday's' post) piqued my curiosity than I was empanelled on a jury for a 5-day medical malpractice trial. This gave me ample time to think through some of the issues of statistics and the law. I will spend my next...

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    Experts and Trials II: True Opinion & Slant

    John Friedman

    I ended my last post by showing, in the context of the brief model I sketched, what the optimal outcome would look like. In practice, though, the court suffers from two problems.

    First, it cannot conduct a broad survey, but must instead rely on those testimonies presented in court. Each side will offer an expert whose "true opinion" is as supportive of their argument as possible, regardless of whether that expert is at all representative of commonly...

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    Experts and Trials IV: Why?

    John Friedman

    In my previous posts on this subject (see here for the most recent), I have explored our legal system's reliance on expert witnesses from game-theoretic and personal perspectives. In this post, I take an entirely different approach, and ask the question: why is our system structured so?

    The first question by many might be: what are the alternatives? The traditional example is the French system, known as the Civil Law system (as opposed to the British-based...

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    Adventures in Identification II: Exposing Corrupt Politicians

    Today we continue our voyage in the treasure quest for identification in observational studies. After our sojourn in Spain two weeks ago, the next stopover is in Brazil, where in a recent paper Claudio Ferraz and Frederico Finan discovered a nice natural experiment that allows to estimate the effect of transparency on political accountability. Many in the policy world are agog over the beneficial impact of...

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    Extreme Values

    Michael Kellermann

    Every year, the host university of the Political Methodology conference invites a local scholar from some other discipline to share his or her research with the political science methods community. This year's special presentation, by James Elsner of the Florida State University Department of Geography, was sadly prescient. Professor Elsner's talk, "Bayesian Inference of Extremes: An Application in Modeling Coastal Hurricane Winds," applied extreme value theory in a Bayesian...

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    Exxon-tainted research?

    A few bloggers at other sites (Concurring Opinions and Election Law Blog) have pointed out an interesting footnote in the Supreme Court's recent decision on punitive damages in the Exxon Valdez case. Justice Souter took note of experimental research on jury decisionmaking done by Cass Sunstein, Daniel Kahneman, and others, but then dismissed it for the purposes of the decision because Exxon had contributed funding for the research:...

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    FAQs about Statistical Interactions

    I am writing a short essay about the connection and distinction between indirect effect and interaction effect for a methodological class and find the following website very helpful to clarify some of the FAQs on that subject. The website is maintained by Professor Regina Branton at the Department of Political Science of Rice University.

    http://www.ruf.rice.edu/~branton/interaction/faqshome.htm

    Also check out the mediation item at Wikipedia and its great references.

    ...

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    Fernanda Viegas and Martin Wattenberg on Data Visualization

    Dear Applied Statistics Community,

    Please join us for this week's installment of the Applied Statistics workshop, where Fernanda Viegas and Martin Wattenberg will be presenting their talk entitled, "From Wikipedia to Visualization and Back'. The authors provided the following abstract for their 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...

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    Firefox plugin for webscraping

    Students here are often interested in how to efficiently collect information from the web. Here's a basic tool: iMacros is a plugin for the Firefox browser and lets you create macros to automate tasks or collect information. It exploits that all elements in html pages can be identified and hence targeted. For example a form field will have an ID that iMacros finds and fills with a value of your choice or click a specified button for you. Two nice features are that you can record your own macros without...

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    Fixing Math Education by Making It Less Enjoyable?

    Justin Grimmer

    In a recent Brookings Institution report on the mathematics scores of junior high and high school students from different nations uncovers some paradoxical correlations. Using standardized test scores, the report shows that nations with the highest scores also have the students with the lowest confidence in their math ability and the lowest levels of enjoyment from learning math. This is evident in American students, with high confidence and enjoyment, but only with...

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    Follow-up on Robins' Talk ("A Bold Vision of Artificial Intelligence and Philosophy")

    A few blog readers asked for more information about Jamie Robins' talk today and the "pinch of magic and miracle" he promised in the abstract. I wanted to offer my non-expert report on the presentation, particularly because Jamie and his coauthors don't yet have a paper to circulate.

    Jamie organized the talk around a research scenario in which five variables are measured in trillions of independent experiments and the task is to uncover the causal process relating the variables. (His example...

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    Freaks And "Parameter"

    Jim Greiner

    In a previous post, I briefly described the joint Law School/Department of Statistics course I’m currently co-teaching in which law students act as lawyers and quantitative students act as experts in simulated litigation. I’ll be writing about some of the lessons learned from this course in blog entries, especially lessons about what is quickly becoming the course’s central challenge for the students: communication between those with quantitative training and...

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