Posts Tagged ‘ Significance ’

How to face the mid-life crisis in A/B Testing

December 10, 2014
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There have been few updates as I was working on things for other people. One of these things showed up today. Here is an excerpt from the beginning of my new article on HBR: For over 10 years and at three companies, I set up and ran A/B testing programs, in which we test a new offer with half a sample against a control group which doesn’t get a new…

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Gelman explains why massive sample sizes to chase after tiny effects is silly

November 21, 2014
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What a lucky day I found time to catch up on some Gelman. He posted about the Facebook research ethics controversy, and I'm glad to see that he and I have pretty much the same attitude (my earlier post is here.). It's a storm in a teacup. Gelman makes two other points about the Facebook study--unrelated to the ethics--which are very important. First, he said: if we happen to see…

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Binge Reading Gelman

June 23, 2014
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Binge Reading Gelman

As others binge watch Netflix TV, I binge read Gelman posts, while riding a train with no wifi and a dying laptop battery. (This entry was written two weeks ago.) Andrew Gelman is statistics’ most prolific blogger. Gelman-binging has become a necessity since I have not managed to keep up with his accelerated posting schedule. Earlier this year, he began publishing previews of future posts, one week in advance, and…

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What the DST researchers actually found

June 16, 2014
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What the DST researchers actually found

To add to my prior post, having now read the published paper on the effect of DST on heart attacks, I can confirm that I disagree with the way the publicist hired by the journal messaged the research conclusion. And some of the fault lies with the researchers themselves who appear to have encouraged the exaggerated claim. Here is the summary of the research as written up by the researchers…

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Another PR effort to scare you into clicking

June 11, 2014
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Another PR effort to scare you into clicking

From Andrew Gelman's blog, I learned about a paper that makes the claim that daylight savings time could kill you. (Andrew links to this abstract, which is from a poster presentation at a meeting of the American College of Cardiology, and later published as a supplement in the ACC Journal; one of his readers found the published paper.) There is also a press release sponsored by the Journal with the…

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Title IX, causal claims, and plausibility in statistics

May 21, 2014
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Andrew Gelman discusses a paper and blog post by Ian Ayres on the Freakonomics blog. Their main result is summarized as: We find that a ten percentage-point increase in state-level female sports participation generates a five to six percentage-point rise in the rate of female secularism, a five percentage-point increase in the proportion of women who are mothers, and a six percentage-point rise in the proportion of mothers who, at…

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The trouble with some journal-published papers

May 14, 2014
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The trouble with some journal-published papers

In the popular science genre, one often comes across "published in a peer-reviewed journal" as a certificate of authenticity. Given that the authors of such reports or books typically do not have the technical chops to understand the materials deeply, it's not a surprise that they require third-party validation. However, "published in a peer-reviewed journal" is pretty weak. I just read a paper published in a peer reviewed journal that…

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Beyond the surface of poll numbers

May 6, 2014
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This Upshot piece about increasing prevalence of tattoos in the U.S. linked to a Fox News Poll, summarized here by Fox News reporters. The statistics say that 20% of voters haves at least one tattoo, up from 13% in 2007. Fourteen percent haves two or more tattoos, up from 8%. The problem with poll result reporting are many. Let me count them: How should we interpret those numbers? One thing…

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A clear picture of power and significance in A/B tests

May 3, 2014
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A clear picture of power and significance in A/B tests

A/B tests are one of the simplest reliable experimental designs. Controlled experiments embody the best scientific design for establishing a causal relationship between changes and their influence on user-observable behavior. “Practical guide to controlled experiments on the web: listen to your customers not to the HIPPO” Ron Kohavi, Randal M Henne, and Dan Sommerfield, Proceedings […] Related posts: Bandit Formulations for A/B Tests: Some Intuition Sample size and power for…

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An anthropological study shows why complete data designs are counterproductive

May 1, 2014
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An anthropological study shows why complete data designs are counterproductive

I saw Joe N.'s tweet asking me about a study of how professors spend their time, reported by Lisa Wade at Sociological Images. This is an anthropological study, something that I am not at all familiar with although the people in the field seem to believe that they can make statistically valid observations. I'm glad the author of the study, John Ziker, wrote a (really) long article describing what he…

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