When I read through parts of the Cass review when it came out, I thought the same as Chris here. Big difference between "absence of evidence" and "evidence of absence", and even academics sometimes struggle with the difference. If there's absence of evidence, you need more evidence! Good letter.

I went back in time as far as I could go, and the first post was DELETED. bsky.app/profile/mlob... Damn.

I despise that "novelty" is a driver of anything to do with publication in epidemiology. It is an incentive to p-hack, data mine, fabricate data, conduct analyses seeking specific results etc. If it is robust and adds to the evidence base, then it should be published.

King Charles argued on Friday that, thanks to early diagnosis, his treatment will be reduced in the New Year. He urged people to take up cancer screening saying: “Early diagnosis quite simply saves lives.” www.bbc.co.uk/news/a... 1/10

So...my undergrad thesis student is doing a quality analysis of studies found in meta-analyses. She identified a few and we contacted the authors to request their effect sizes and other variables for the studies in their papers. Here's what happened: scientiapsychiatrica.com/index.php/Sc...

Going through references is such a mind-numbing, irritating (paywalls, shitty journals, etc.), and thankless task, but absolutely necessary to ensure statements are backed up by evidence. I wrote about this a while ago when trying to find evidence for a claim: seanharrison.blog/2025/02/21/i...

All screening causes harm. Some screening causes benefit. You need studies and stats to tell you whether the benefit outweighs the harm.

IHT at 100%: 50% to the Government as tax, 50% into a fund to provide every kid with a "starting out" grant at 18 years old. Tackle inequality at source and help out people just starting, many of whom will need the money most. "But they'll just set up trusts!" -- k, guess we'll do nothing!

I believe, for policy, the effect size doesn't matter by itself (unless it's 0): it only matters in conjunction with costs and QALYs (or similar), including side-effects. Cost-effectiveness matters most: a smaller effect size but better side-effect profile or cheaper intervention may be better.

Ok, I've thought about this for too long, and come to yet another conclusion about Lord's paradox. seanharrison.blog/2025/10/12/y...

Ok, I've thought about this for too long, and come to yet another conclusion about Lord's paradox. seanharrison.blog/2025/10/12/y...

I hadn't heard of Lord's paradox before, so looked it up. Pearl gives Lord's version in full. www.degruyterbrill.com/document/doi... What struck me was that I didn't see "regression to the mean" in either the wiki article or Pearl's paper, but... the second statistician is ignoring that?

I think the key thing in using LLMs to write code is the answer to this question: "Why have you written this line of code?" If the answer is: "Because I needed a logistic regression controlling for [X] to give an OR, interpreted as...", great, no different to using StackOverflow...

Something I've thought about but haven't seen written yet: There *should* be an observational association between autistic children and pain relief in pregnancy. Austism is highly genetic, so the chance of mothers being autistic is high (even if undiagnosed).

This (the idea of using LLMs as stand-ins for humans) is so very, very dumb. Legitimately surprised there's enough published work using this method that it needed refuting, but good work for doing so!

John Finnemore's Souvenir Programme back for 2025

p=1, bitches

Apt. I didn't know Sean Connery was dead!

It's the same mentality as: "Group has X quality, therefore any member of that group has that quality" (notwithstanding the "group has X quality" is often wrong) At heart, it's laziness, same as every prejudicial -ism. Even if the first statement is correct, the second doesn't follow.

A letter from myself and @jdwilko.bsky.social that expands on this a bit more. Thanks to Fertility and Sterility for the opportunity. doi.org/10.1016/j.fe...

To win a bet, I once flipped a random coin I had in my wallet 20 times, and had it land on heads every time. Think I won 50p. With the right flipping technique, one could absolutely dictate the outcome. With hindsight, I probably should be used that skill to make a heap of money... Oh well.

The person who wrote this list seems to have no idea either what each of these jobs entails or the limits of LLMs. tbf it could be an AI-generated list. That'd be on-brand.

I wrote a thing: press.asimov.com/articles/asp... If you're interested in whether willow bark = aspirin, it might be interesting! If not, it still might be interesting!

There was Guardian opinion piece about remove age limits from voting entirely: www.theguardian.com/books/2025/j... I thought about it, and can't come up with objections to removing the voting age that don't equally apply to older groups.

Ha, possibly a true dichotomy: 67% of Britons use "Fuck" regularly 33% of Britons "Have a negative view of swearing" Possible for overlap, of course, but the numbers line up so well!

I wrote a thing: press.asimov.com/articles/asp... If you're interested in whether willow bark = aspirin, it might be interesting! If not, it still might be interesting!

I have a history with wasps. When I was a very young child, one was in my wellie, and stung me repeatedly (presumably after being mildly crushed). When I was slightly older, one stung me repeatedly in bed. No one believed me until they found the wasp in a crumpled heap under the covers.

Unless there's an immensely good reason, don't combine studies with a 26x difference in SD. They're almost certainly not measuring the same thing, so the meta-analysis results are meaningless. (on top of interrogate insane results)

Ignoring the criticism about how this can possibly help in doing things with Government policy, I did enjoy solving the puzzle. Answer below for anyone interested - I'll put it in the alt text so not immediately obvious. It'd help to draw it, but that would give spoilers...

I think my problem is that LLMs don't know anything, it's just word probability. Same as politicians and other people who are absolutely happy to say anything with no thought about the meaning of their words. In both cases, people believe them. But there's no meaning behind any of it. Only words.

Unreferenced claim made in the discussion of a 1987 paper used for the next ~40 years because people keep citing the latest paper citing the claim? Yep, spent a fun weekend chasing references to get that one... seanharrison.blog/2025/02/21/i...

I was saving this for an article, but I want something to refer to when I talk about how I think the best way to fix peer-review is to abolish journals. Long-ish thread, and I'm talking from the perspective of epidemiology, where crappy studies can cause harm to individuals and populations. 1/n

Pretty sure I read something like this last week: "The intervention increased 7-day smoking abstinence (OR: 0.85, 95% CI: 0.79 to 0.90) but not 30-day smoking abstinence (OR: 0.82, 95% CI: 0.60 to 1.01)"

Just wanted to say I read this a while ago, and really liked it. That's all.

I did my PhD in prostate cancer, looking at PSA. During that, when I was 22/23, I did a 5km or 10km run for prostate cancer. I was asked if I wanted a PSA test when I was registering.

I think I've just found a blind spot in school anti-bullying policies. Read my blog here: arc-w.nihr.ac.uk/news/i-think...

Read the methods and results, and it looks... Fine? Headline aside, I didn't see anything immediately obviously wrong with the trial, which is really surprising given the results. I initially thought, "they probably just did per protocol", but nope, ITT.

Ok, so 3 initial thoughts: 1. How does one-off screening for cancer reduce cancer incidence over time? I can see how it would reduce diagnoses (e.g. scared to get a repeat screening), but not incidence (unless maybe scared into dietary changes? But by that much?)

That's not what meta-analysis is for, that's not what "consensus" is, you don't decide the analysis method randomly after doing the experiment, and each analysis, if correct, probably has different assumptions and interpretations that can't be meaningfully combined. Otherwise, great...

I agree with @steamtraen.eu on this: I think people who have difficulty with the solution instinctively think that Monty opens a door at random, rather than necessarily a door with a goat behind it. So, I'd go with the "extreme example": 98 goat-doors reinforces it's not random door opening.

Peer Support and Community Interventions Targeting Breastfeeding in the UK: Systematic Review of Qualitative Evidence to Identify Inequities in Participants' Experiences Rhiannon Evans, Caitlyn Donaldson, @ruthgarside.bsky.social et al onlinelibrary.wiley.com/doi/full/10....

#epithoughtfortheday #Ihatehastags When I learned about per protocol analyses in RCTs, I thought "ok, so they're the intervention effect estimate conditional on the person continuing treatment". Maybe, but it's a subgroup analysis of an RCT, so... Maybe/probably not. Thought experiment:

I had laser eye surgery about 15 years ago. Want to hear about it? Don't read on if squeamish...

I had laser eye surgery about 15 years ago. Want to hear about it? Don't read on if squeamish...

"A series of errors" is a *very* generous interpretation!

My book Ultra Women written with @emmajourno.bsky.social is out today. We were originally told that men wouldn't buy this book so there was no market for it (as apparently women don't buy sports books!!!) - we desperately want to prove that marketing person wrong! www.amazon.co.uk/Ultra-Women-...

Got pissed off. Wrote a blog post on the "Drink Champage to stop your heart stopping" thing. Obviously it's shit, but they used methods I've used in a population I've used, and even presented a very similar summary figure to my one, so... seanharrison.blog/2025/04/30/d...

This wasn't a study, it's the opinion of some French medics. Who equate watching TV with crossing the road unassisted, alcohol, and smoking. And just give a handful of references at the end, as if that's good enough. www.theguardian.com/society/2025...

ABCDE x A = EEEEEE Fun 2 minutes there. From www.theguardian.com/sport/2025/m...