Pop Quiz. Let's say you take a Covid-19 antibody test. The test has an accuracy of 90%. To be more specific, both its sensitivity (the proportion of actual positives that are correctly identified as such) and specificity (the proportion of actual negatives that are correctly identified as such) are 90%. The test comes back positive. … Continue reading Base Rate Fallacy

Whenever you do a math calculation, it's a good idea to do a sanity check. The goal is to do a quick test to determine whether the answer could possibly be true. Not that it is true, but that it could be true. Or, to put it another way, to verify that it isn't obviously … Continue reading Sanity Check

I haven't written about Covid-19, because lots of very smart people are already doing great analysis of it. (Of course, there's also been a lot of crappy analysis too, usually by someone with a political ax to grind). But... One thing that struck me recently, is that we're about to embark on a large multiple … Continue reading A Grand Experiment

Today we'll look at debuts of baby names - names that show up on the list for the first time. The original name list dates from 1880, and all of the common names of that era appear on this list. In fact, most of the currently-popular names were in use back then too: of the … Continue reading Baby Name Debuts

Yes, that's from Life of Brian. One interesting trend of baby names is the diversification. Parents are frequently choosing names that are non-traditional/non-standard. Even the most popular names are chosen less frequently than before. To see this change, let's compare 1959, which is very close to the peak of the baby boom, with 2018. The … Continue reading “You’re all different”

The Social Security department puts out a list of names chosen for babies. Every year, this generates a series of news stories about the most popular baby names. The data, which goes back decades, also feeds Wolfram Alpha's database (here is an example). The data is broken down by states, so let's have some fun … Continue reading Baby Names

One last post on the Presidential election data. This one will look at something I call Adjusted Trend. The "trend" part looks at how each county voted, compared to the previous election. The "adjusted" means that I'll adjust for the overall swing for the country as a whole. Here's an example: in the 1996 re-election … Continue reading Adjusted Trend heat maps

In a previous post, I talked about how Americans are increasingly living in 'electoral islands', clumped together mostly with people who vote the same way they do. I've got a way of visualizing this which I'll get to shortly, but first I'd like to show some different types of electoral maps Here's a map from … Continue reading Electoral Islands

I'm going to try to identify "polarizing elections". These are elections where the voting public seems to be heading in different directions (sound familiar?). I identify the amount of "polarization" on a county-by-county basis, comparing the results to the previous election (and adjusting for the overall vote of the US). The further the county is … Continue reading Polarizing Elections

I'm back to looking at presidential voting patterns. In February I looked at how closely states and counties match the country's voting results. This post will look a different question: the consistency of states and counties. Specifically, how consistent is a region's party lean, when compared to the nation as a whole? As an example, … Continue reading More Presidential Voting