It's always frustrating to see media outlets play loose with facts. When I read a headline like "Shake Shack's New Cashier-Free Location Really Does Reduce Wait, So Far," (link) I am expecting to read some evidence that the wait times of customers have decreased. Granted, this is a hard problem because you always need a "control" - something to compare to. And when this is a new restaurant, in a…
A nice article in Zerohedge about the recent rate hike for Tesla owners (link). Of course, Tesla is crying foul. The gist of the story is that Tesla owners tend to get into more crashes and the repair cost is higher than for other brands. The former is a matter of statistics - but also self-selection: in my limited encounters, the first things Tesla owners tell me about their cars…
When Hillary Clinton unexpectedly lost the election in November 2016, it was high time for pundits to espouse their pet theories for the shocking losses suffered by the Democrats at all levels of government. The usual suspects were put on parade, such as “Bernie Bros” who abstained from voting and the “deplorables” who voted against their own interests. For the first time, two unlikely entities faced scrutiny: the social-media giant,…
You probably already saw the video - if not, do yourself a favor, and search for "man forcibly removed from overbooked United flight." Other than the video evidence, which is damning, we don't have many facts, other than assertions made by various parties, repeated endlessly on social media and mainline media. Some facts, such as the United CEO claiming the passenger was "belligerent," is an assault on the meaning of…
The World Economic Forum published this chart: The "EF EPI Score" is a measure of English proficiency. So the evidence is clear as day: "Better English and Income Go Hand in Hand," as their headline blares. Last time I was in the New York subway, the panhandler spoke good English. What's a blogger to do? I pulled out the EPI scores from the EPI report, and downloaded the Gross National…
This New York Times article draws attention to real trends in the financial investments industry but gets completely lost in the smoke around those pushing "machines" and "data". The trend most concerning to the investments industry is the sustained, large-scale outflow of money from "actively-managed" funds, mutual funds being the biggest category of such. The industry makes loads of money from management fees by promoting the idea that investors are…
You've heard me say often, numbersense is the most important quality for good data analysts; little did I know that numbersense would become the new requirement for healthy American democracy. From the first day in office, the new President is at war with numbers (over attendance figures at his inauguration). But I believe that getting to the bottom of data-driven claims is a bi-partisan issue: while it is obvious that…
In class last week, I discussed this New York Times article with the students. One of the claims in the article is that the U.S. News ranking of colleges is under threat by newcomers whose rankings are more relevant because they more directly measure outcomes such as earnings of graduates. This specific claim in the article makes me head hurt: "If nothing else, earnings are objective and, as the database…
Last week, my Columbia students discussed this nice article in the New York Times called "The Most Detailed Map of Gay Marriages in America". (link) The center of the article is this map: I asked the students to identify the problem that this dataviz is supposed to address. Someone responded that it tells us where gay married couples are found geographically. I asked her what is the answer to the…
The management at New York Times was smart enough to create a data science team but apparently the newsroom has not yet been exposed to STAT 101. Today, NYT printed this headline: "Top C.E.O. Pay Fell -- Yes, Fell -- in 2015" (link to article). I immediately thought, not so fast, are they talking about average pay or median pay. Anyone who has taken STAT 101 knows that when analyzing…
