You’ve got the whole world in your portfolio

December 29, 2011 | dan

A famous finance professor once told us that good diversification meant holding everything in the world. Fine, but in what proportion? Suppose you could invest in every country in the world. How much would you invest in each? In a market-capitalization weighted index, you'd invest in each country in proportion ... [Read more...]

Keep your files in sync for free

November 19, 2011 | dan

It is not uncommon to have two computers at work, four at home and a server out on the wild, wild internet (that's what we have, anyway ... wait, we forgot one in London). How to keep all these files in sync? Here are our file synchronization tips. [Read more...]

Searching for inaccurate literals in R

May 29, 2011 | Derek-Jones

In creating the numbers tool I wanted to be able to do two things, 1) obtain information about what source did by matching the numeric literals it contained against a database of ‘interesting’ values (now with over 14,000 entries) and 2) flag possible incorrect numeric literals (e.g., 3.1459265 when 3.14159265 had been intended in ... [Read more...]

EC2 AMI for scientific computing in Python and R

April 11, 2011 | Drew Conway

Like many people who crunch numbers frequently, I have increasingly been integrating Amazon’s cloud computing services into my daily workflow. In particular, I have been using their elastic cloud computing (EC2) on a regular basis. The service is an excellent way to offload computationally intensive work from your laptop ... [Read more...]

The housing bubble by city

March 17, 2011 | dan

The housing bubble by city. Miami sailed high and fell far. Detroit rose modestly and but dropped more than it went up. Dallas held steady. DC is enjoying a bit of renewed growth, but are in and New York yet to fall? [Read more...]

Area plots unmasked

December 15, 2010 | dan

RESULTS OF THE GREAT AREA PLOT QUIZ If you are the type of reader who remembers things from last week, you may remember the great area plot quiz we had running. This week, we are excited to announce that the results are in. The plot above shows answers to the ... [Read more...]

Once again, chart critics and graph gurus welcome

December 10, 2010 | dan

HOW TO DISPLAY A LINE PLOT WITH COUNT INFORMATION? In a previously-mentioned paper Sharad and your DSN editor are writing up, there is the above line plot with points. The area of each point shows the count of observations. It’s done in R with ggplot2 (hooray for Hadley). We ... [Read more...]

My First R Package: infochimps

November 20, 2010 | Drew Conway

I have finally taken the plunge and created my first R package! As frequent readers will know, I often sing the praises of infochimps, a startup out of Austin, TX attempting to be the world’s data clearinghouse. While infochimps is an excellent resource for data sets, they also provide ... [Read more...]

Visualizations of US neighborhoods by race and ethnicity

September 22, 2010 | dan

HOMOPHILY + MAPS WITHOUT MAPPING SOFTWARE In the past, Decision Science News has posted about homophily (“birds of a feather shop together“) and cool, lightweight visualizations (“maps without map packages in R“). Today, both topics come together in Eric Fischer’s fascinating set of images on Flickr called “Race and Ethnicity”(*).  ... [Read more...]

Birds of a feather shop together

August 31, 2010 | dan

PREDICTING CONSUMER BEHAVIOR FROM SOCIAL NETWORKS This week, Decision Science News is doing a special cross-posting with Messy Matters. The post below is by Sharad Goel and describes work that he and your Decision Science News editor Dan Goldstein are jointly undertaking at Yahoo! Do you know what the #$*! your ... [Read more...]

Which chart is better?

August 10, 2010 | dan

CHART CRITICS, GRAPHICS CURMUDGEONS, COME ONE COME ALL Once upon a time there was this graph (graph 1). Andrew Gelman went all graphics curmudgeon on it, calling it an “ugly, sloppy bit of data graphics“, so it became this graph (graph 2). Now the question is, which is better: graph 2 or graph 3? ... [Read more...]

The counterfactual GPS!

July 23, 2010 | dan

WHAT IF YOUR GPS TOLD YOU WHAT WOULD HAVE HAPPENED IF YOU HAD TAKEN THE OTHER ROUTE? Not long ago, your Decision Science News editor was planning a trip to a book group meeting along with another member. The monthly book group takes place in Cove Neck Long Island, about ...
[Read more...]

userR! 2010 Videos to be Hosted at Rchive

July 20, 2010 | Drew Conway

Today, I am packing up the car and heading south to my old home, Washington, DC, for the useR! 2010 conference, which is being held at the National Institute of Standards and Technology. Incidentally, where I was an intern in the Information Technology Lab during college. If you are not able ... [Read more...]

Tuesday’s child is full of probability puzzles

May 28, 2010 | dan

COUNTERINTUITIVE PROBLEM, INTUITIVE REPRESENTATION Blog posts about counterintuitive probability problems generate lots of opinions with a high probability. Andrew Gelman and readers have been having a lot of fun with the following probability problem: I have two children. One is a boy born on a Tuesday. What is the probability ... [Read more...]

Must Have Software

May 28, 2010 | John Mount

Having worked with Unix (BSD, HPUX, IRIX, Linux and OSX), Windows (NT4, 2000, XP, Vista and 7) for quite a while I have seen a lot of different software tools. I would like to quickly exhibit my “must have” list. These are the packages that I find to be the single “must ... [Read more...]
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