Pareto at Melos

September 11, 2012
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Attention conservation notice: Advertises writings of economic theorists, utterly detached from the real world, as part of a long-running argument among academic bloggers. Because Brad DeLong wants to revive a discussion from two years ago about "Ho...

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Tweaking Resource-Allocation-by-Tweaking (Introduction to Statistical Computing)

September 11, 2012
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In which we make incremental improvements to our code for planning by incremental improvements. Assignment, code. Introduction to Statistical Computing

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Lab: Flow Control and the Urban Economy (Introduction to Statistical Computing)

September 11, 2012
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In which we use nonlinear least squares to fit the West et al. model. Lab, R code; solutions. Introduction to Statistical Computing

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Writing and Calling Functions (Introduction to Statistical Computing)

September 11, 2012
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Lecture 4: Just as data structures tie related values together into objects, functions tie related commands together into objects. Declaring functions. Arguments (inputs) and return values (outputs). Named arguments, defaults, and calling functions....

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Writing Multiple Functions (Introduction to Statistical Computing)

September 11, 2012
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Lecture 5: Using multiple functions to solve multiple problems; to sub-divide awkward problems into more tractable ones; to re-use solutions to recurring problems. Value of consistent interfaces for functions working with the same object, or doing si...

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Domino effect

September 10, 2012
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Domino effect

I had quickly read something about this on the papers earlier today, and tonight I saw the episode of Dispatches, presenting the "school dinner scandal". There are several points that were raised by the documentary which are really, really interesting....

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The Forest of Advocacy: Visualizations of Big Data Regarding Politics

September 10, 2012
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The Forest of Advocacy: Visualizations of Big Data Regarding Politics

Can big data reveal hidden patterns of political contributions? A new initiative, The Forest of Advocacy [vispolitics.com], developed by what is described as "LazerLAB and the Northeastern Centers for Computational Social Science and Digital Humanitie...

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The Forest of Advocacy: Visualizations of Big Data Regarding Politics

September 10, 2012
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The Forest of Advocacy: Visualizations of Big Data Regarding Politics

Can big data reveal hidden patterns of political contributions? A new initiative, The Forest of Advocacy [vispolitics.com], developed by what is described as "LazerLAB and the Northeastern Centers for Computational Social Science and Digital Humanitie...

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The pebbles of academia

September 10, 2012
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The pebbles of academia

I have just been awarded a certificate for successful completion of the Conflict of Interest Commitment training (I barely passed). Lately, I have been totally swamped by administrative duties and have had little time for actual research. The experienc...

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Item Response Theory: Developing Your Intuition

September 10, 2012
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Item Response Theory: Developing Your Intuition

Suppose that you accepted my argument from the last two posts on halo effects and bifactor models.  As you might recall, I argued that when respondents complete rating scales, they predominating rely on their generalized impression with a more min...

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Example 10.1: Read a file byte by byte

September 10, 2012
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Example 10.1: Read a file byte by byte

More and more makers of electronic devices use standard storage media to record data. Sometimes this is central to the device's function, as in a camera, so that the data must be easy to recover. Other times, it's effectively incidental, and the devi...

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Visualizing US commute times and congestion

September 10, 2012
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Visualizing US commute times and congestion

Robert Allison posted a map that shows the average commute times for major US cities, along with the proportion of the commute that is attributed to traffic jams and other congestion. The data are from a CEOs for Cities report (Driven Apart, 2010, p. 45). Robert use SAS/GRAPH software to [...]

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Update on Levitt paper on child car seats

September 10, 2012
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A few years ago I noted the following quote from applied microeconomist Steven Levitt: Is it surprising that scientists would try to keep work that disagrees with their findings out of journals? When I told my father that I [Levitt] was sending my work saying car seats are not that effective to medical journals, he [...]

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Exercise helps statisticians

September 10, 2012
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Exercise helps statisticians

Statistics is a rather sedentary job, and, over the years, I found my effectiveness decreasing as I found fewer “peak” hours in the day. I also gained a lot of weight. The number of migraines I experienced went from about two a year to about once a...

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INLA functions (continued)

September 10, 2012
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INLA functions (continued)

I have polished up one of the two functions I've thought of implementing for INLA and it's now available in the development version of the R package. So if you've got INLA installed in your R version (see how you can do it here, if you don't), you...

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Factor Analysis: A Short Introduction, Part 1

September 10, 2012
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Factor Analysis: A Short Introduction, Part 1

The key concept of factor analysis is that multiple observed variables have similar patterns of responses because of their association with an underlying latent variable, the factor, which cannot easily be measured. For example, people may respond similarly to questions about income, education, and occupation, which are all associated with the latent variable socioeconomic status.

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R Package Vignettes with Markdown

September 10, 2012
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What is the best resource to learn an R package? Many R users know the almighty question mark ? in R. For example, type ?lm and you will see the documentation of the function lm. If you know nothing about a package, you can take a look at the HTML help...

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Storytelling and Focus

September 10, 2012
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Storytelling and Focus

There are many differences between data analysis and presentation. One that is often overlooked is the need to focus a story to just the essential points, and not overload it with unnecessary detail. Minard’s famous map is a great example of reduction to the bare minimum. Minard’s famous map of Napoleon’s invasion of Russia summarizes the fate of some 420,000 men over more than six months. They were not alone,…

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Converting a Markdown File to PDF Using Pandoc

September 10, 2012
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Working with knitr and markdown is a great way to share quick reports with colleagues, but in cases where IE8 is still the dominant browser, shipping an HTML file with embedded graphics is a non-starter. IE8 does not support the Data URI format used to...

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R Package Vignettes with Markdown

Note: since R 3.0.0, you can build Markdown vignettes naturally; see https://yihui.name/knitr/demo/vignette/ for details. What is the best resource to learn an R package? Many R users know the almighty question mark ? in R. For example, type ?lm and you will see the documentation of the function lm. If you know nothing about a package, you can take a look at the HTML help by help.start() where you can…

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Why resampling is better than hypothesis tests and confidence intervals

September 9, 2012
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Why resampling is better than hypothesis tests and confidence intervals

I love to read George Cobb’s writing. In person I found him a kind and intelligent man, and a generous host. But his writing is laugh-out-loud funny at times, provocative and inspiring. I suspect that he may be the indirect … Continue reading →

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Core minus one!

September 9, 2012
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Core minus one!

Jean-Michel Marin visited me in Paris last week and, besides taking part in Pierre’s PhD defence, we made enough progress to close two more chapters of the new edition of Bayesian Core (soon to be Bayesian Essentials with R!) This follows the good work session we had in Carnon where we also completed two chapters [...]

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Run keeping to keep running

September 9, 2012
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Run keeping to keep running

To keep up with the Olympic spirit, and on Marta's insistence, I think I've started doing some running. I've gone twice in a week: last Saturday we first went to Kent to pick up some stuff we bought off Ebay (in the process we first stopped by Tunbridg...

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