Today I’ve been doing some work on a project for a Data Assimilation class, implementaing an ensemble Kalman Filter that uses a big, coupled SEIR model and Google Flu Trends from 2003 to track flu incidence and estimate model parameters (based on some previous work by my advisor). When I first started drafting everything I assumed that each region was just a 10th of the total US population, because it was simpler than trying to track down actual population data. This a pretty bad assumption, and I think it’s has been causing some inference quirks like concluding that the outbreak was a complete pandemic in every region (this, plus living in Boulder and having just visited Las Vegas has meant that “The Stand” is looming large in the back of my mind this week).
Anyways, I’ve been trying to do a bettter with my population estimates. Unfortunately the HHS website was a total bust for easy-to-locate regional population numbers and various abuses of Google’s fancy search bar such as “population MA+NY” also turned up bupkiss. “What I really want”, I thought to myself, “is a software that can interpret my mangled, semi-symbolic queries, search a giant database, and then return the queried value to me. Something like…a…computational knowledge…engine…” Cue flashback to freshman year of undergrad; the “MyMathLab” homework website open in one tab and WolframAlpha in the other, feverishly copy+pasting problems 10 minutes before midnight.
I was actually a pretty big fan of WolframAlpha for my entire undergrad career, not just that freshman year where it was mainly a means to cheat on my homework. I was totally unfamiliar with Mathematica at the time, and so having another tool for troubleshooting or double checking my calculus (especially one that could accept pretty mangled or gnarly input) was invaluable in some of my upper level physics courses. I even went so far as to buy the phone app; it was only $2.99, but still I think that indicates a certain amount of affection for the software and loyalty to the brand. Iron Man has JARVIS, Holmes has Watson, and I have Stephen Wolfram (apologies to Dr. Wolfram if you are, for some reason, reading this).
Back to the present: I took my search efforts over to WolframAlpha and beheld glorious success. The website can actually accept a query of the form “(Arkansas+Louisiana+New Mexico+Oklahoma,+Texas population in 2003)/(population of United States in 2003)” and return a value (that I’m just going to assume is accurate; error bars would be sweet, but beggars can’t be choosers). That’s more or less the point of this post. WolframAlpha (and Mathematica) really is an amazing product. I’m not sure what the upper bound of sophistication would be if you were to try and fully integrate it into your inference procedures, but even at this level it’s really amazing. And now Wolfram Research also make reference guide apps for the iPhone for various special topics like cat breeds, so really the sky is the limit here.