Blog Archives

New season of Grey’s Anatomy with Exponential Random Graph Models

October 8, 2012
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In a previous post we used the web of sexual contacts among characters on the Grey’s Anatomy television show to look at some social network analysis using R. To celebrate the beginning of the new season, Ben Lind has put … Continue reading →

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Rcpp is smoking fast for agent-based models in data frames

July 11, 2012
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In a previous post, I discussed different approaches to speeding up some loops in data frames. In particular, R data frames provide a simple framework for representing large cohorts of agents in stochastic epidemiological models, such as those representing disease … Continue reading →

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Calculating the mixing matrix and assortativity coefficient with igraph in R

April 16, 2012
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The mixing matrix of a graph gives the density of edges between vertices with different characteristics. The mixing matrix for a given igraph object can be calculated using the following function: The assortativity coefficient, based on Newman’s paper, can be … Continue reading →

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R can write R code, too

April 14, 2012
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In a recent blog post by CMastication, a little meme puzzle is presented with the introduction that a preschooler could solve it in 5-10 minutes, a programmer in an hour. I took the bait. The original problem goes like this: … Continue reading →

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Speeding up agent-based simulations with data frames in R

April 16, 2011
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In health economics it is common to use agent-based simulations for exploring epidemiological models, prevention policies, and clinical interventions, among other things. In C++ I enjoy using object-oriented design to build these agent-based models. It feels so natural. In R, … Continue reading →

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Using R and clinical heuristics to explore the Heritage Health Prize: what do we gain?

April 13, 2011
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The recent opening of the Heritage Health Prize both represents a milestone and raises a cautionary flag. On the one hand, crowdsourced analytics prizes have never tackled anything so noble (not to discount predicting movie ratings), but on the other … Continue reading →

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The structure of twitter participant relationships in conversations around #Libya, #Bieber, and #Rstats

April 4, 2011
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I am a recent comer to twitter, and it took me a few weeks to figure out what this was all about. Who are all these people tweeting each other and what do all these trending hashtags mean? Do these … Continue reading →

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Grey’s Anatomy Network of Sexual Relations

March 25, 2011
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This all began with an introductory presentation about social network analysis to a group of medical students.  What better way to grab their attention than with attractive, fake doctors having sex on television?  Naturally this led to the dense network … Continue reading →

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