Sample size hypocrisy – Stuart Ritchie edition

Predictably, Stuart Ritchie doesn’t like our Ashkenazim intelligence paper (Why doesn’t he? He dislikes all group difference research. See more below.) He makes a big deal of the fact that the sample size for Wisconsin Ashkenazim was only 53. (He neglects to mention that the comparison group numbered 2000 Christians). It might seem like most people dislike our study, but we did get a lot of private feedback from researchers who praised it. This situation arises when there is a stigma against expressing the other view.

Good thing Stuart wouldn’t publish studies with small sample sizes himself. Or would he? Now his list of publications is long and impressive in content, but I found some “embarrassing” studies of his own.

PARTICIPANTS AND METHODS: Sixty-one schoolchildren (aged 7–12 years) with reading difficulties were assessed by an Irlen diagnostician. We used a within-subject study design to examine differences in reading rate across 3 conditions: using an overlay of a prescribed color; using an overlay of a nonprescribed color; and using no overlay. In a subset of 44 children, all of whom had a diagnosis of Irlen syndrome, we also used a between-group design to test the effects of Irlen colored overlays on a global reading measure.

Colored filters are used to treat Irlen syndrome (IS), a controversial disorder posited to be the cause of a substantial proportion of reading difficulties. Previously, we found that Irlen colored filters do not produce any short‐term alleviation of reading difficulties in schoolchildren aged 7–12. Here, we tested whether colored filters show benefits with longer‐term use, in a subset of the original sample. We measured reading rate with and without filters in 18 children diagnosed with IS, who had been using the filters for 1 year, and compared the progression of their reading ability across the year against 10 poor‐reader control children. The Irlen‐treatment group did not read any faster when using their colored filter, and showed no disproportionate gain in reading progress across the year compared to controls. We conclude that Irlen filters do not benefit reading, even after 1 year of use.

On Twitter, Stuart explains these as:

Ok, so just some old tiny studies. But…

RESEARCH DESIGN AND METHODS Fourteen adults with type 1 diabetes underwent a hyperinsulinemic, hypoglycemic clamp on two separate occasions. Before one glucose clamp, the participants stayed awake overnight to induce sleep deprivation. Participants were randomized and counterbalanced to the experimental condition. Cognitive function tests were performed before and during hypoglycemia and for 90 min after restoration of normoglycemia.

Fifty-one patients with SLE (mean age 48.8 ± 14.3 years) were included. Mean diffusivity (MD) was significantly higher in all white matter fibre tracts in SLE patients versus age-matched healthy controls (p<0.0001). Fatigue in SLE was higher than a normal reference range (p<0.0001) and associated with lower MD (β = −0.61, p=0.02), depression (β = 0.17, p=0.001), anxiety (β = 0.13, p=0.006) and higher body mass index (β = 0.10, p=0.004) in adjusted analyses. Poorer cognitive function was associated with longer SLE disease duration (p=0.003) and higher MD (p=0.03) and, in adjusted analysis, higher levels of IL-6 (β = −0.15, p=0.02) but not with MD. Meta-analysis (10 studies, n=261, including the present study) confirmed that patients with SLE have higher MD than controls.

Stuart also seems to consider people who research group differences to be “losers”, “weirdos” and “obsessives”.

His disparaging remark about independent scholars is also noteworthy, considering that we are arguably living through a revival of the independent scientist (they call it citizen science this time) as a byproduct of the open science movement. His tweet follows the usual style of biased descriptions for researchers doing group differences work. If someone investigated causes of diabetes for years, one might call them “rigorous” or “meticulous”, or “thorough”, but if they instead research something Staurt doesn’t like they are “obsessive”. The double standards live on. The most likely explanation is that Stuart is trying hard to make IQ research seem palatable to his left-leaning university colleagues. As Nathan Cofnas has shown, normal scientific practice kind of breaks down when it comes to group differences research.

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