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Multilevel modeling in Stan improves goodness of fit — literally.

John McDonnell sends along this post he wrote with Patrick Foley on how they used item-response models in Stan to get better clothing fit for their customers: There’s so much about traditional retail that has been difficult to replicate online. In some senses, perfect fit may be the final frontier for eCommerce. Since at Stitch […]

Regression to the mean continues to confuse people and lead to errors in published research

David Allison sends along this paper by Tanya Halliday, Diana Thomas, Cynthia Siu, and himself, “Failing to account for regression to the mean results in unjustified conclusions.” It’s a letter to the editor in the Journal of Women & Aging, responding to the article, “Striving for a healthy weight in an older lesbian population,” by […]

Trying to make some sense of it all, but I can see it makes no sense at all . . . stuck in the middle with you

“Mediation analysis” is this thing where you have a treatment and an outcome and you’re trying to model how the treatment works: how much does it directly affect the outcome, and how much is the effect “mediated” through intermediate variables. Fabrizia Mealli was discussing this with me the other day, and she pointed out that […]

Ways of knowing in computer science and statistics

Brad Groff writes: Thought you might find this post by Ferenc Huszar interesting. Commentary on how we create knowledge in machine learning research and how we resolve benchmark results with (belated) theory. Key passage: You can think of “making a a deep learning method work on a dataset” as a statistical test. I would argue […]

Answering the question, What predictors are more important?, going beyond p-value thresholding and ranking

Daniel Kapitan writes: We are in the process of writing a paper on the outcome of cataract surgery. A (very rough!) draft can be found here, to provide you with some context: Using standard classification methods (Python sklearn, with synthetic oversampling to address the class imbalance), we are able to predict a poor outcome […]

When does the quest for beauty lead science astray?

Under the heading, “please blog about this,” Shravan Vasishth writes: This book by a theoretical physicist [Sabine Hossenfelder] is awesome. The book trailer is here. Some quotes from her blog: “theorists in the foundations of physics have been spectacularly unsuccessful with their predictions for more than 30 years now.” “Everyone is happily producing papers in […]

Data science teaching position in London

Seth Flaxman sends this along: The Department of Mathematics at Imperial College London wishes to appoint a Senior Strategic Teaching Fellow in Data Science, to be in post by September 2018 or as soon as possible thereafter. The role will involve developing and delivering a suite of new data science modules, initially for the MSc […]

What is the role of qualitative methods in addressing issues of replicability, reproducibility, and rigor?

Kara Weisman writes: I’m a PhD student in psychology, and I attended your talk at the Stanford Graduate School of Business earlier this year. I’m writing to ask you about something I remember you discussing at that talk: The possible role of qualitative methods in addressing issues of replicability, reproducibility, and rigor. In particular, I […]

Power analysis and NIH-style statistical practice: What’s the implicit model?

So. Following up on our discussion of “the 80% power lie,” I was thinking about the implicit model underlying NIH’s 80% power rule. Several commenters pointed out that, to have your study design approved by NSF, it’s not required that you demonstrate that you have 80% power for real; what’s needed is to show 80% […]

Bayesians are frequentists

Bayesians are frequentists. What I mean is, the Bayesian prior distribution corresponds to the frequentist sample space: it’s the set of problems for which a particular statistical model or procedure will be applied. I was thinking about this in the context of this question from Vlad Malik: I noticed this comment on Twitter in reference […]

Chasing the noise in industrial A/B testing: what to do when all the low-hanging fruit have been picked?

Commenting on this post on the “80% power” lie, Roger Bohn writes: The low power problem bugged me so much in the semiconductor industry that I wrote 2 papers about around 1995. Variability estimates come naturally from routine manufacturing statistics, which in semicon were tracked carefully because they are economically important. The sample size is […]

Stan goes to the World Cup

Leo Egidi shares his 2018 World Cup model, which he’s fitting in Stan. But I don’t like this: First, something’s missing. Where’s the U.S.?? More seriously, what’s with that “16.74%” thing? So bogus. You might as well say you’re 66.31 inches tall. Anyway, as is often the case with Bayesian models, the point here is […]

About that quasi-retracted study on the Mediterranean diet . . .

Some people asked me what I thought about this story. A reporter wrote to me about it last week, asking if it looked like fraud. Here’s my reply: Based on the description, there does not seem to be the implication of fraud. The editor’s report mentioned “protocol deviations, including the enrollment of participants who were […]

Do women want more children than they end up having?

Abigail Haddad writes: In

Can somebody please untangle this one for us? Are centrists more, or less, supportive of democracy, compared to political extremists?

OK, this is a nice juicy problem for a political science student . . . Act 1: “Centrists Are the Most Hostile to Democracy, Not Extremists” David Adler writes in the New York Times: My research suggests that across Europe and North America, centrists are the least supportive of democracy, the least committed to its […]

Josh “hot hand” Miller speaks at Yale tomorrow (Wed) noon

Should be fun.

Global shifts in the phenological synchrony of species interactions over recent decades

Heather Kharouba et al. write: Phenological responses to climate change (e.g., earlier leaf-out or egg hatch date) are now well documented and clearly linked to rising temperatures in recent decades. Such shifts in the phenologies of interacting species may lead to shifts in their synchrony, with cascading community and ecosystem consequences . . . We […]

A style of argument can be effective in an intellectual backwater but fail in the big leagues—but maybe it’s a good thing to have these different research communities

Following on a post on Tom Wolfe’s evolution-denial trolling, Thanatos Savehn pointed to this obituary, “Jerry A. Fodor, Philosopher Who Plumbed the Mind’s Depths, Dies at 82,” which had lots of interesting items, including this: “We think that what is needed,” they wrote, “is to cut the tree at its roots: to show that Darwin’s […]

We’re putting together a list of big, high profile goals that proved far more challenging than people had anticipated circa 1970

Palko writes: The postwar era (roughly defined here as 1945 to 1970) was a period of such rapid and ubiquitous technological and scientific advances that people naturally assumed that this rate of progress would continue or even accelerate. This led not just futurists like Arthur C Clarke but also researchers in the fields to underestimate […]

The necessity—and the difficulty—of admitting failure in research and clinical practice

Bill Jefferys sends along this excellent newspaper article by Siddhartha Mukherjee, “A failure to heal,” about the necessity—and the difficulty—of admitting failure in research and clinical practice. Mukherjee writes: What happens when a clinical trial fails? This year, the Food and Drug Administration approved some 40 new medicines to treat human illnesses, including 13 for […]