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    Causation and Manipulation II: The Causal Effect of Gender?

    Jens Hainmueller

    In a recent post, Jim Greiner asked whether we adhere to the principle of "no causation without manipulation." This principle, if true, raises the question of whether it makes sense to talk about the causal effect of gender.

    The Rubin/Holland position on this is clear: it makes no sense to talk about the causal effect of gender because what manipulation and thus what counterfactual one has in mind (a sex-transformation surgery?) is clearly ill-defined. One...

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    Causation and Manipulation VII: The Cartoon Version

    Doging Bill Collectors

    As Tailor (A) fits customer (B) and calls out measurements, college boy (C) mistakes them for football signals and makes a flying tackle at clothing dummy (D). Dummy bumps head against paddle (E) causing it to pull hook (F) and throw bottle (G) on end of folding hat rack (H) which spreads and pushes head of cabbage (I) into net (J). Weight of cabbage pulls cord (K) causing shears (L) to cut string (M). Bag of sand (N) drops on scale (O) and pushes broom (P) against pail of whitewash (Q)...

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    CCCSN - Devon Brewer

    The Cambridge Colloquium on Complexity and Social Networks is sponsoring a talk tomorrow that may be of some interest to readers of this blog. Details below:

    "Taking Person, Place, and Time Seriously in Infectious Disease Epidemiology and
    Diffusion Research"

    Devon D. Brewer, University of Washington

    Thursday, April 5, 2007
    12:00 - 1:30 p.m.
    CGIS North, 1737 Cambridge Street, Room N262

    Abstract: Social scientists and field epidemiologists have long appreciated the role of social networks in diffusion processes. The cardinal goal of descriptive...

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    Censoring Due to Death

    D. James Greiner

    I'm interested in the problem of "censoring due to death" within the framework of the Rubin Causal Model ("RCM").

    As readers will know, the RCM is a framework for studying the effects of causes in which the science is represented via a set of potential outcomes for each unit. (A potential outcome is the value the dependent variable would take on if the treatment variable had a certain value, whether or not the treatment variable actually had that value). An assignment mechanism decides what treatment (e.g., active treatment or control) a unit receives and...

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    Censoring Due to Death, cont'd

    John F. Friedman

    The problem of "censoring by death" also surfaces up in a number of economic contexts. For instance, firms that go bankrupt as a result of poor corporate policies will not appear in many datasets, making any analysis of the impact of other financial events biased upwards. This problem has particularly plagued the literature on the impacts of corporate restructuring and leveraged buyouts (LBOs) of distressed firms. Since these firms are at high risk of failure by nature of their inclusion in the study in the first place, such firms exit the sample at high...

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    Censoring Due to Death, cont'd, & A Visit To Harvard

    Censoring, cont'd
    John F. Friedman

    Continuing from the most recent post, for the economist, perhaps a more interesting incidence of this statistical problem is not researchers making this error within the literature but consumers making misjudgments in the marketplace. (Since most people approach problems in their lives with less rigor than a statistician, perhaps this is not surprising). In particular, once consumers make these inference mistakes, economic theory suggests that firms will take advantage. Edward Glaeser wrote at length on this phenomenon in 2003 in "Psychology...

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    Censoring Due to Death: A Statistics Symposium

    Drew Thomas

    The Harvard Dept. of Statistics kicks off its 2005-2006 seminar series on Monday, September 19 with a talk by the father of the Rubin Causal Model himself, Prof. Donald Rubin. An entertaining speaker if there ever was one, Prof. Rubin will give a firsthand account of his research to all who are interested.

    The talk will be held in Science Center 705 at 4:00; a reception will follow. Looking forward to seeing all interested parties in attendance.

    Posted by...

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    Censoring or Truncation Due to "Death"?: What’s the Question? (Part II)

    Jim Greiner

    In my last post, I pointed out that when presented with a causal inference situation of treatment, intermediate outcome, and final outcome, we have to be careful to define a sharp question of interest. Sometimes, we’re interested in the ITT, or the effect of the treatment on the final outcome. At other times, we’re interested in the effect of the intermediate outcome on the final outcome, and the treatment is our best way of manipulating the intermediate outcome so as to draw causal inferences.

    In my view, these principles are important in the...

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    Censoring or Truncation Due to ``Death": What’s the Question?

    Jim Greiner

    A few weeks ago, Felix Elwert gave a bang-up presentation at the Wednesday seminar series on the effect of cohabitation on divorce rates (see here). One of the most interesting points I took away from the discussion was the following: in some social science situations in which a treatment is followed by an intermediate outcome, then by a final outcome, we might be interested in different causal questions. One causal question is the effect of the treatment on the...

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    Chaney on "Economic Shocks, Religion and Political Influence"

    We hope you can join us at the Applied Statistics Workshop this Wednesday, March 23rd, when we are excited to have Eric Chaney from the Department of Economics here at Harvard. Eric will be presenting his paper entitled “Revolt on the Nile: Economic Shocks, Religion and Political Influence.” You’ll find an abstract below. As usual, we will begin at 12 noon with a light lunch and wrap up by 1:30pm.

    “Revolt on the Nile: Economic Shocks,...

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    Cheating for Honest People

    Let me follow up on yesterday’s post by Jim Greiner.

    Jim’s problem: He’s touring the country touting tools for increased honesty in applied statistical research, only to be asked, effectively, for recommendations about using these tools to cheat more effectively. Yay academic job market.

    Jim’s example goes like this: An analyst is asked to model the effect of a treatment, T, on the outcome, Y, while controlling for a bunch of confounders, X. To minimize the potential for data dredging we give the analyst only the treatment and the observed potential confounders to model the...

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    Choosing variances in general linear models

    Today I'm going to talk about a particular problem from my own research and will outline a method for choosing variances in general linear models (GLMs), but I am also asking a question.

    The standard setup of GLMs is (roughly) the following. One hypothesizes that the conditional mean of the outcome variable (y), E[y|x], can be expressed as a function of a linear predictor x'b, or:

    E[y|x]=?(x'b).

    The function ? is referred to as the link function. Common choices for ? include both the...

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    Christakis on "The Spread of Health Phenomena In Social Networks"

    Please join us this Wednesday when Nicholas Christakis--Professor, Department of Sociology (Harvard University) and Medical Sociology (Harvard Medical School)--who will be present "Eat Drink and Be Merry: The Spread of Health Phenomena In Social Networks". Nicholas provided the following abstract:


    Our work has involved the quantitative investigation of whether and how various health-related phenomena might spread from person to person. For example, we explored the nature and extent of person-to-person spread of obesity. We developed a densely interconnected network of 12...

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    Citing and Finding Data

    How much slower would scientific progress be if the near universal standards for scholarly citation of articles and books had never been developed. Suppose shortly after publication only some printed works could be reliably found by other scholars; or if researchers were only permitted to read an article if they first committed not to criticize it, or were required to coauthor with the original author any work that built on the original. How many discoveries would never have been made if the titles of books and articles in libraries changed unpredictably, with no link back to the old...

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    Clay Public Lecture: "Technology-driven statistics"

    The Clay Mathematics Institute and the Harvard Mathematics Department are sponsoring a lecture by Terry Speed from the Department of Statistics at Berkeley on "Technology-driven statistics," with a focus on the challenges presented to statistical theory and practice presented by the massive amounts of data that are generated by modern scientific instruments (microarrays, mass spectrometers, etc.). These issues have not yet been as salient in the social sciences, but they are clearly on the horizon. The talk is at 7PM tonight (Oct. 30) in Science Center B at Harvard. The abstract for the...

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    Climate change and conflict in Africa

    A paper just published in PNAS finds that armed conflict in Africa in recent decades has been more likely in hotter years, and projects that warming in the next twenty years will result in roughly 54% more conflicts and almost 400,000 more battle deaths. This is an important paper and it probably will attract significant attention from the media and policymakers. I think it's a good paper too -- seems fairly solid in the empirics, nice presentation, and admirably forthright about the limitations of the study. I'...

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    Coarsened at Random

    Jim Greiner

    I’m the “teaching fellow” (the “teaching assistant” everywhere but Harvard, which has to have its lovely little quirks: “Spring” semester beginning in February, anyone?) for a course in missing data this semester, and in a recent lecture, an interesting concept came up: coarsened at random.

    Suppose you have a dataset in which you know or suspect that some of your data values are rounded. For example, ages of youngsters might be given to the nearest year or half-year. Or perhaps in a survey, you’ve gotten some respondents’ incomes only within...

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    Coding Analysis Toolkit looking for beta testers

    A recent message to the Polmeth mailing list announced that a research group at the University of Pittsburgh is looking for beta testers for some new coding reliability software that they have developed:

    The Coding Analysis Toolkit (or “CAT”) was developed in the summer of 2007. The system consists of a web-based suite of tools custom built from the ground-up to facilitate efficient and effective analysis of text datasets that have been coded using the commercial-off-the-shelf package ATLAS.ti (http://www.atlasti.com). We...
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    Cog Sci Conf

    Amy Perfors

    The annual meeting of the Conference of the Cognitive Science Society took place in late July. Amid a slew of interesting debates and symposia, one paper stood out as having particularly interesting implications from the methodological perspective. The paper, by Navarro et. al., is called "Modeling individual differences with Dirichlet processes" (pdf found here).

    The basic...

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