Redefine Statistical Significance Part IX: Gelman and Robert Join the Fray, But Are Quickly Chased by Two Kangaroos

Andrew Gelman and Christian Robert are two of the most opinionated and influential statisticians in the world today. Fear and anguish strike into the heart of the luckless researchers who find the fruits of their labor discussed on the pages of the duo’s blogs: how many fatal mistakes will be uncovered, how many flawed arguments will be exposed? Personally, we…

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Redefine Statistical Significance Part VIII: How 88 Authors Overlooked a Giraffe and Sailed Straight into an Iceberg

The key point of the paper “Redefine Statistical Significance” is that p-just-below-.05 results should be approached with care. They should perhaps evoke curiosity, but they should not receive the blanket endorsement that is implicit in the bold claim “we reject the null hypothesis”. The statistical argument is straightforward and has been known for over half a century: for p-just-below-.05 results,…

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Redefine Statistical Significance Part VII: Bursting the Bubble

The paper Redefine Statistical Significance reveals an inconvenient truth: p-values near .05 are evidentially weak. Such p-values should not be used “for sanctification, for the preservation of conclusions from all criticism, for the granting of an imprimatur.” (Tukey, 1962, p. 13 — NB: Tukey was referring to statistical procedures in general, not to p-values or p-just-below-.05 results specifically). Unfortunately, in…

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Redefine Statistical Significance Part VI: Another Nail in the .05 Coffin

In our previous posts about the paper “Redefine Statistical Significance”, two concrete examples corroborated the general claim that p-just-below-.05 results constitute weak evidence against the null hypothesis. We compared the predictive performance of H0 (effect size = 0) to the predictive performance of H1 (specified by a range of different prior distributions on effect size) and found that for a…

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Redefine Statistical Significance Part V: A Wizard Walks Into a Sauna and Starts Pawing at a Pizza…

In previous posts we provided detailed Bayesian reanalyses of two “p-just-below-.05” experiments (i.e., red, rank, and romance, and flag-priming). For both experiments, the evidence against the null hypothesis was relatively weak, and this supported the main claim from the paper “Redefine Statistical Significance” (and the 2016 claim by the American Statistical Association, and the claim made by statisticians throughout the last…

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