Origin of the Texas Sharpshooter

The picture of the Texas sharpshooter is taken from an illustration by Dirk-Jan Hoek (CC-BY). The infamous Texas sharpshooter fires randomly at a barn door and then paints the targets around the bullet holes, creating the false impression of being an excellent marksman. The sharpshooter symbolizes the dangers of post-hoc theorizing, that is, of finding your hypothesis in the data.…

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Redefine Statistical Significance XIII: The Case of Ego Depletion

The previous blog post discussed the preprint “Ego depletion reduces attentional control: Evidence from two high-powered preregistered experiments”. Recall the preprint abstract:           “Two preregistered experiments with over 1000 participants in total found evidence of an ego depletion effect on attention control. Participants who exercised self-control on a writing task went on to make more errors…

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Two Pitfalls of Preregistration: The Case of Ego Depletion

Several researchers have proposed that the capacity for mental control is a limited resource, one that can be temporarily depleted after having engaged in a taxing cognitive activity. This hypothetical phenomenon — called ego depletion — has been hotly debated, and its very existence has been called into question. We ourselves are in the midst of a multi-lab collaborative research…

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Redefine Statistical Significance Part XII: A BITSS debate with Simine Vazire and Daniel Lakens

This Tuesday, one of us [EJ] participated in a debate about –you guessed it– the α = .005 recommendation from the paper ‘Redefine Statistical Significance’. The debate was organized as part of the Annual Meeting of the Berkeley Initiative for Transparency in the Social Sciences (BITSS), and the two other discussants were Simine Vazire and Daniel Lakens. The debate was…

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How to Prevent Your Dog from Getting Stuck in the Dishwasher

This week, Dorothy Bishop visited Amsterdam to present a fabulous lecture on a topic that has not (yet) received the attention it deserves: “Fallibility in Science: Responsible Ways to Handle Mistakes”. Her slides are available here. As Dorothy presented her series of punch-in-the-gut, spine-tingling examples, I was reminded of a presentation that my Research Master students had given a few…

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Redefine Statistical Significance Part XI: Dr. Crane Forcefully Presents…a Red Herring?

The paper “Redefine Statistical Significance” continues to make people uncomfortable. This, of course, was exactly the goal: to have researchers realize that a p-just-below-.05 outcome is evidentially weak. This insight can be painful, as many may prefer the statistical blue pill (‘believe whatever you want to believe’) over the statistical red pill (‘stay in Wonderland and see how deep the…

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Bayes Factors for Stan Models without Tears

For Christian Robert’s blog post about the bridgesampling package, click here. Bayesian inference is conceptually straightforward: we start with prior uncertainty and then use Bayes’ rule to learn from data and update our beliefs. The result of this learning process is known as posterior uncertainty. Quantities of interest can be parameters (e.g., effect size) within a single statistical model or…

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The Butler, The Maid, And The Bayes Factor

This post is based on the example discussed in Wagenmakers et al. (in press). The Misconception Bayes factors are a measure of absolute goodness-of-fit or absolute pre- dictive performance. The Correction Bayes factors are a measure of relative goodness-of-fit or relative predictive performance. Model A may outpredict model B by a large margin, but this does not imply that model…

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