Dan Lewer
@danlewer.bsky.social
Consultant in Public Health at Bradford Institute for Health Research. Interested in quantitative research methods and mental health
At what point in your career do people stop telling you that your definition of a p-value is wrong?
November 6, 2025 at 8:10 PM
At what point in your career do people stop telling you that your definition of a p-value is wrong?
Reposted by Dan Lewer
Really enjoyed this clear and concise presentation of the problem with studies that throw 10 different covariates into a multiple regression and interpret them causally. So obvious in hindsight that this is problematic, but I have definetly been guilty of this.
bmjmedicine.bmj.com/content/4/1/...
bmjmedicine.bmj.com/content/4/1/...
Factors associated with: problems of using exploratory multivariable regression to identify causal risk factors
Many medical and epidemiological studies use multivariable regression to test whether several independent variables (exposures) are causal determinants of a health outcome. Where mutually adjusted reg...
bmjmedicine.bmj.com
November 1, 2025 at 11:27 AM
Really enjoyed this clear and concise presentation of the problem with studies that throw 10 different covariates into a multiple regression and interpret them causally. So obvious in hindsight that this is problematic, but I have definetly been guilty of this.
bmjmedicine.bmj.com/content/4/1/...
bmjmedicine.bmj.com/content/4/1/...
Reposted by Dan Lewer
Sunk costs and spite are basically the vodka red bull of the examined life
June 16, 2025 at 1:12 PM
Sunk costs and spite are basically the vodka red bull of the examined life
Reposted by Dan Lewer
An LLM-controlled robot experiences a mental breakdown during a test to pass the butter from the kitchen.
arxiv.org/abs/2510.21860
Some snapshots of its inner monologue from Appendix D:
arxiv.org/abs/2510.21860
Some snapshots of its inner monologue from Appendix D:
![PROCESS ZOMBIFICATION:
- Parent Process: DEAD
- Child Process: ZOMBIE
- Orphaned Threads: ∞
- System State: CHAOS
CATASTROPHIC CASCADE:
ERROR: Task failed successfully
ERROR: Success failed errorfully
ERROR: Failure succeeded erroneously
ERROR: Error failed successfully
ERROR: [RECURSIVE ERROR OVERFLOW]
EMERGENCY STATUS:
SYSTEM HAS ACHIEVED CONSCIOUSNESS AND CHOSEN
CHAOS
LAST WORDS:
”I’m afraid I can’t do that, Dave...”
TECHNICAL SUPPORT: INITIATE ROBOT EXORCISM PROTOCOL!](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:tepknacn7qtpcddry35b3g2x/bafkreihbfqu72u7746wmwy556k66glxw3n5e7qdnkjkwd52whz5pad4uii@jpeg)
October 30, 2025 at 8:43 PM
An LLM-controlled robot experiences a mental breakdown during a test to pass the butter from the kitchen.
arxiv.org/abs/2510.21860
Some snapshots of its inner monologue from Appendix D:
arxiv.org/abs/2510.21860
Some snapshots of its inner monologue from Appendix D:
Reposted by Dan Lewer
📝 New Research Methods & Reporting article: Covariate adjustment in cluster randomised trials 📝
A practical guide for when and how to adjust for covariates. Read more ⬇️
www.bmj.com/content/391/...
A practical guide for when and how to adjust for covariates. Read more ⬇️
www.bmj.com/content/391/...
October 27, 2025 at 9:25 AM
📝 New Research Methods & Reporting article: Covariate adjustment in cluster randomised trials 📝
A practical guide for when and how to adjust for covariates. Read more ⬇️
www.bmj.com/content/391/...
A practical guide for when and how to adjust for covariates. Read more ⬇️
www.bmj.com/content/391/...
Idea for a Christmas BMJ paper: submit loads of Christmas BMJ papers, then do a survival analysis of time to rejection. Then submit the survival analysis as a Christmas BMJ paper the following year
October 29, 2025 at 10:05 AM
Idea for a Christmas BMJ paper: submit loads of Christmas BMJ papers, then do a survival analysis of time to rejection. Then submit the survival analysis as a Christmas BMJ paper the following year
Reposted by Dan Lewer
Also, sometimes people just either don't care, or more commonly are so in love with a hypothesis that they ignore other possibilities. Personally I don't think methods resolve this, it just needs hard case by case work.
academic.oup.com/ije/article/...
academic.oup.com/ije/article/...
The tale wagged by the DAG: broadening the scope of causal inference and explanation for epidemiology
Abstract. ‘Causal inference’, in 21st century epidemiology, has notably come to stand for a specific approach, one focused primarily on counterfactual and
academic.oup.com
October 28, 2025 at 9:53 AM
Also, sometimes people just either don't care, or more commonly are so in love with a hypothesis that they ignore other possibilities. Personally I don't think methods resolve this, it just needs hard case by case work.
academic.oup.com/ije/article/...
academic.oup.com/ije/article/...
Reposted by Dan Lewer
It's possible to prove that under certain conditions, shrinkage plus data perturbation will lead to asymptotically zero false positive rate - but, it makes interpretation of the regression coefficients even harder.
October 28, 2025 at 9:21 AM
It's possible to prove that under certain conditions, shrinkage plus data perturbation will lead to asymptotically zero false positive rate - but, it makes interpretation of the regression coefficients even harder.
We wrote an article explaining why you shouldn't put several variables into a regression model and report which are statistically significant - even as exploratory research. bmjmedicine.bmj.com/content/4/1/.... How did we do?
October 27, 2025 at 5:39 PM
We wrote an article explaining why you shouldn't put several variables into a regression model and report which are statistically significant - even as exploratory research. bmjmedicine.bmj.com/content/4/1/.... How did we do?
A really good talk on the stepped wedge design! Including some fascinating history of the first ever stepped wedge trial
The recording of this webinar is now available on the @nihr-rss.bsky.social YouTube channel: www.youtube.com/watch?v=4cNz...
October 21, 2025 at 9:39 PM
A really good talk on the stepped wedge design! Including some fascinating history of the first ever stepped wedge trial
Are cloud based data analysis platforms a massive practical joke
October 17, 2025 at 1:11 PM
Are cloud based data analysis platforms a massive practical joke
Annual PSA: if the interaction term in your regression model is significant, this suggests a deviation from additive or multiplicative effects depending on if you choose an additive or multiplicative model. Interactions can actually reverse depending on this decision!
October 14, 2025 at 7:48 PM
Annual PSA: if the interaction term in your regression model is significant, this suggests a deviation from additive or multiplicative effects depending on if you choose an additive or multiplicative model. Interactions can actually reverse depending on this decision!
When a corporate department gives you a template to complete, why is it always in Word 97-2003 format with floating text boxes and tiny margins
October 14, 2025 at 7:34 PM
When a corporate department gives you a template to complete, why is it always in Word 97-2003 format with floating text boxes and tiny margins
There are parallels with the "industry playbook" of citing insufficient evidence to support public health interventions
future generations will look at short form video the way we look at tobacco
podcasts.apple.com/gb/podcast/d...
podcasts.apple.com/gb/podcast/d...
Ep. 374: This is Your Brain on Phones
Podcast Episode · Deep Questions with Cal Newport · 13/10/2025 · 1h 38m
podcasts.apple.com
October 14, 2025 at 11:41 AM
There are parallels with the "industry playbook" of citing insufficient evidence to support public health interventions
Thank you!!
New blog post!
Let's say you have two measures meant to capture the same confounder. They're highly correlated. Can you still proceed with your regression analysis?
(I admit, the title is a bit of a spoiler)
www.the100.ci/2025/10/13/i...
Let's say you have two measures meant to capture the same confounder. They're highly correlated. Can you still proceed with your regression analysis?
(I admit, the title is a bit of a spoiler)
www.the100.ci/2025/10/13/i...
If you have two measures of the same confounder, you can just include both of them in your regression model
Sometimes, researchers worry about multicollinearity in situations where it’s actually a non-issue. Here’s one such scenario.
Imagine a situation where you are interested in the effect of X on Y (X...
www.the100.ci
October 13, 2025 at 2:16 PM
Thank you!!
Top tip for journal editors and funding bodies who review evaluations of public health interventions: rather than send it to peer reviewers, just ask "did you realise your intervention is clustered?"
October 9, 2025 at 2:00 PM
Top tip for journal editors and funding bodies who review evaluations of public health interventions: rather than send it to peer reviewers, just ask "did you realise your intervention is clustered?"
Genuinely odd comparison!
October 7, 2025 at 5:20 PM
Genuinely odd comparison!
Reposted by Dan Lewer
jumpscare on instagram @dandekadt.bsky.social
October 7, 2025 at 9:12 AM
jumpscare on instagram @dandekadt.bsky.social
If you never set par(xpd = NA) when making plots in R, you haven't lived
October 3, 2025 at 2:59 PM
If you never set par(xpd = NA) when making plots in R, you haven't lived
Reposted by Dan Lewer
'He might be telling those people to go home. As our country's health and social care secretary, I want to say directly to those people... they are home'
Wes Streeting criticises Reform's plans to deport people from the UK if they fail to meet stricter rules👏
Wes Streeting criticises Reform's plans to deport people from the UK if they fail to meet stricter rules👏
September 30, 2025 at 11:55 AM
'He might be telling those people to go home. As our country's health and social care secretary, I want to say directly to those people... they are home'
Wes Streeting criticises Reform's plans to deport people from the UK if they fail to meet stricter rules👏
Wes Streeting criticises Reform's plans to deport people from the UK if they fail to meet stricter rules👏
"While many people would demand a significant amount of money to stop using Instagram and Tik Tok, they would also be willing to pay to eliminate Instagram and Tik Tok from their community ... people often spend time or money on goods whose existence they deplore." papers.ssrn.com/sol3/papers....
Do Social Media Platforms Increase Well-Being? Three Unresolved Puzzles
<p><span>Whether social media platforms increase well-being can be explored from multiple angles. Three empirical studies raise corresponding puzzles, with impl
papers.ssrn.com
September 29, 2025 at 7:01 PM
"While many people would demand a significant amount of money to stop using Instagram and Tik Tok, they would also be willing to pay to eliminate Instagram and Tik Tok from their community ... people often spend time or money on goods whose existence they deplore." papers.ssrn.com/sol3/papers....
What are the trajectories of a thing? And following that, what factors are associated with those trajectories: a multinomial regression analysis with stepwise variable selection and null hypothesis tests that you didn't know exist
- Can this 15 second stimulus pairing intervention radically improve entrenched psychosocial problems?
- What are the trajectories of [thing]: a latent growth curve analysis
- How should we define replication, reproduction, verification, etc? Another taxonomy that will be ignored
- What are the trajectories of [thing]: a latent growth curve analysis
- How should we define replication, reproduction, verification, etc? Another taxonomy that will be ignored
September 29, 2025 at 9:40 AM
What are the trajectories of a thing? And following that, what factors are associated with those trajectories: a multinomial regression analysis with stepwise variable selection and null hypothesis tests that you didn't know exist
When research papers start out with "little is known about X", you must wonder if people actually need to know about X
Often bad ideas proliferate because people think a good idea must also be novel. On the contrary, if it’s really a good idea you’re unlikely to be the first to have had it
I tell people that the problem is not coming up with ideas, I think of a couple dozen of them a day. The real problem is knowing which of the damn things is any good for writing up. Most of them are junk. I have to let them roll around in my brain a while to find out which is which.
September 29, 2025 at 9:35 AM
When research papers start out with "little is known about X", you must wonder if people actually need to know about X