Publications by dan
Winning streaks in baseball
HOW RARE ARE STREAKS? The New York Mets recently won 11 games in a row, which got a lot of attention. How likely is it that a given baseball team will win 11 games in a row by chance, if its probability of winning a single game is 50%? The plot below shows that if a baseball team plays 100 seasons of 162 games, they’ll have an streak of 11 win...
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Chances of going to college based on parent’s income
INCOME PERCENTILES AND INCOMES PAINT DIFFERENT PICTURES The amazing team at the New York Times have a “You Draw It” feature in The Upshot in which readers try their hands at drawing a graph. The graph should show the probability of a child going to college based on their parents’ percentile in the income distribution. As a cool added featu...
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When did same-sex marriage laws become effective by state?
CORRELATION WITH REPUBLICAN VOTING IN THE 2012 PRESIDENTIAL ELECTION Click to enlarge In light of the good news today that the Supreme Court ruled that same-sex couples have the right to marry in the United States, we thought we’d look at when same-sex marriage laws became effective by state (if they did at all) before today. Noting that same ...
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How long do prison escapees go before being caught?
A DOZEN YEARS OF ESCAPE DATA FROM NEW YORK STATE Click to enlarge The recent prison break in upstate New York got us wondering how long prison escapes tend to last. We found some data on prison escapes in New York State. See the dot plot above. We then found a table in the Atlantic on perhaps more skillful inmates who managed to stay on the run...
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Job opening with Morningstar’s behavioral science team
CHICAGO BASED POSITION The Group: On the Behavioral Insights Team, we use behavioral science to help people engage with and improve their finances. We then run rapid, digital experimental studies to determine what works, and what doesn’t, and publicize the results. The Role: Help millions of people retire with dignity and in comfort. Morningst...
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Visualizing population density
MANHATTAN IS MORE EXTREME THAN YOU THINK IN POPULATION DENSITY Slinging numbers around all day, one adage we believe is that most surprising statistics are wrong. But here’s one that’s not: When you look at the 100 most populous counties in the USA, Manhattan (aka New York County) has about twice the population density of the next densest co...
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Most soccer matches are within one goal of 1-0
ANALYSIS OF A LOW-SCORING SPORT Recently, our friend and co-author Sid Suri predicted that a soccer match would end 2-1. This got us thinking. Suppose you didn’t say which team would score 2 and which would score 1. And suppose people considered you “close” if you got within one goal of 2-1 (so 1-0, 1-1, 2-1, 3-1 or 2-2 would be close). Ho...
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The representative reviewers project for the SJDM conference
MAKING SURE THE REVIEWERS REFLECT THE MEMBERSHIP Click to enlarge Perhaps because it is an election year in the US, we’ve been thinking a lot about proportional representation. The Society for Judgment and Decision Making (SJDM) is a diverse academic society, with people coming from about seven academic fields (or groups of related fields). Se...
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What are the most educated counties in the US?
CENSUS DATA ON EDUCATIONAL ATTAINMENT BY COUNTY People ask us “what are the most educated counties in the USA”? It turns out the census keeps track of this sort of thing. We found a table called ACS_14_1YR_S1501.csv in the American Community Survey; look for stuff on educational attainment by county. And it was an easy bit of R to get the an...
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Can’t compute the standard deviation in your head? Divide the range by four.
TESTING A HEURISTIC TO ESTIMATE STANDARD DEVIATION Click to enlarge Say you’ve got 30 numbers and a strong urge to estimate their standard deviation. But you’ve left your computer at home. Unless you’re really good at mentally squaring and summing, it’s pretty hard to compute a standard deviation in your head. But there’s a heuristic y...
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