Paul Madley-Dowd
@pmadleydowd.bsky.social
Research Fellow in Medical Statistics and Health Data Science at the University of Bristol
Have you ever tried to implement multiple imputation with several incomplete variables? How do you know whether MI will be valid for your data? We have just published an easy to use algorithm using modifications to DAGs (now they're colourful) to aid decision making with MI
doi.org/10.1093/aje/...
doi.org/10.1093/aje/...
November 26, 2025 at 11:37 AM
Have you ever tried to implement multiple imputation with several incomplete variables? How do you know whether MI will be valid for your data? We have just published an easy to use algorithm using modifications to DAGs (now they're colourful) to aid decision making with MI
doi.org/10.1093/aje/...
doi.org/10.1093/aje/...
Reposted by Paul Madley-Dowd
Reposted by Paul Madley-Dowd
When can a 10% improvement be worse than a 5% one? New post on vibe coding and 'volatility tax':
kucharski.substack.com/p/the-hidden...
kucharski.substack.com/p/the-hidden...
Vibe coding and 'volatility tax'
The value of predictable improvement
kucharski.substack.com
September 13, 2025 at 9:06 AM
When can a 10% improvement be worse than a 5% one? New post on vibe coding and 'volatility tax':
kucharski.substack.com/p/the-hidden...
kucharski.substack.com/p/the-hidden...
Does anyone have any thoughts on digital twins in clinical trials or in-silico trials?
September 3, 2025 at 9:48 AM
Does anyone have any thoughts on digital twins in clinical trials or in-silico trials?
Reposted by Paul Madley-Dowd
1/ NEW R PACKAGE! For estimating the impact of potential interventions on multiple mediators in countering exposure effects (led by @cttc101.bsky.social)
- Paper👉 tinyurl.com/ye26jsps
- Package👉 tinyurl.com/yuh4kens
Thread shows published examples of how the method can be used! #EpiSky #CausalSky
- Paper👉 tinyurl.com/ye26jsps
- Package👉 tinyurl.com/yuh4kens
Thread shows published examples of how the method can be used! #EpiSky #CausalSky
tinyurl.com
July 10, 2025 at 1:30 AM
1/ NEW R PACKAGE! For estimating the impact of potential interventions on multiple mediators in countering exposure effects (led by @cttc101.bsky.social)
- Paper👉 tinyurl.com/ye26jsps
- Package👉 tinyurl.com/yuh4kens
Thread shows published examples of how the method can be used! #EpiSky #CausalSky
- Paper👉 tinyurl.com/ye26jsps
- Package👉 tinyurl.com/yuh4kens
Thread shows published examples of how the method can be used! #EpiSky #CausalSky
Reposted by Paul Madley-Dowd
🚨 Funded PhD opportunity 🚨 Work with large-scale electronic health record data from #OpenSAFELY to optimise vaccine effectiveness estimation for respiratory viruses.
Apply here 👉 www.findaphd.com/phds/project...
Apply here 👉 www.findaphd.com/phds/project...
July 4, 2025 at 9:39 AM
🚨 Funded PhD opportunity 🚨 Work with large-scale electronic health record data from #OpenSAFELY to optimise vaccine effectiveness estimation for respiratory viruses.
Apply here 👉 www.findaphd.com/phds/project...
Apply here 👉 www.findaphd.com/phds/project...
Reposted by Paul Madley-Dowd
For those of you using sibling analysis, perhaps you'll find this useful 🥳: www.medrxiv.org/content/10.1...
Moving beyond risk ratios in sibling analysis: estimating clinically useful measures from family-based analysis
Objective: Findings from family-based analyses, such as sibling comparisons, are often reported using only odds ratios or hazard ratios. We demonstrate how this can be improved upon by applying the ma...
www.medrxiv.org
May 17, 2025 at 9:00 AM
For those of you using sibling analysis, perhaps you'll find this useful 🥳: www.medrxiv.org/content/10.1...
Reposted by Paul Madley-Dowd
Fantastic news! This is entirely attributable to all my colleagues—everyone from mentors to students—who have made this possible🎉🎉
news.ki.se/safer-medica...
news.ki.se/safer-medica...
Safer medications for pregnant women and children
Viktor H. Ahlqvist, postdoc at the Institute of Environmental Medicine (IMM), receives 3,000,000 SEK in a Postdoctoral Grant from the Swedish Society for Medical Research (SSMF) for the project “Advan...
news.ki.se
March 27, 2025 at 3:18 PM
Fantastic news! This is entirely attributable to all my colleagues—everyone from mentors to students—who have made this possible🎉🎉
news.ki.se/safer-medica...
news.ki.se/safer-medica...
Reposted by Paul Madley-Dowd
It’s my understanding that with the parametric g-formula you use the outcome model to predict the outcome for each subject, independently of whether they are censored. And you take its mean considering ALL N subjects. If the pot. outcome has some NA, I’d still sum and divide by N.
Stupid question:
Stupid question:
March 24, 2025 at 6:26 PM
It’s my understanding that with the parametric g-formula you use the outcome model to predict the outcome for each subject, independently of whether they are censored. And you take its mean considering ALL N subjects. If the pot. outcome has some NA, I’d still sum and divide by N.
Stupid question:
Stupid question:
Reposted by Paul Madley-Dowd
New publication led by @proflouisemarston.bsky.social using multiple imputation to target a hypothetical estimand in a pandemic restriction-free world for a trial in
schizophrenia - demonstrating the potential impact of the pandemic on the trial results
schizophrenia - demonstrating the potential impact of the pandemic on the trial results
Exploring the effect of COVID-19 restrictions on the Social Functioning Scale in a clinical trial of Antipsychotic Reduction: using multiple imputation to target a hypothetical estimand - Journal of Clinical Epidemiology www.jclinepi.com/article/S089...
Exploring the effect of COVID-19 restrictions on the Social Functioning Scale in a clinical trial of Antipsychotic Reduction: using multiple imputation to target a hypothetical estimand
Many trials are affected by unforeseen events after recruitment has commenced. The
aim of this study is to explore a hypothetical strategy for dealing with an intercurrent
event that occurred during t...
www.jclinepi.com
March 18, 2025 at 8:27 AM
New publication led by @proflouisemarston.bsky.social using multiple imputation to target a hypothetical estimand in a pandemic restriction-free world for a trial in
schizophrenia - demonstrating the potential impact of the pandemic on the trial results
schizophrenia - demonstrating the potential impact of the pandemic on the trial results
Final version published so time to talk about it: doi.org/10.1093/aje/...
When using multiple imputation to account for missing data we often use auxiliary variables (variables included in the imputation model but not the analysis model) to 1) reduce bias and 2) improve statistical efficiency.
When using multiple imputation to account for missing data we often use auxiliary variables (variables included in the imputation model but not the analysis model) to 1) reduce bias and 2) improve statistical efficiency.
Analyses using multiple imputation need to consider missing data in auxiliary variables
Abstract. Auxiliary variables are used in multiple imputation (MI) to reduce bias and increase efficiency. These variables may often themselves be incomple
doi.org
February 19, 2025 at 10:25 AM
Final version published so time to talk about it: doi.org/10.1093/aje/...
When using multiple imputation to account for missing data we often use auxiliary variables (variables included in the imputation model but not the analysis model) to 1) reduce bias and 2) improve statistical efficiency.
When using multiple imputation to account for missing data we often use auxiliary variables (variables included in the imputation model but not the analysis model) to 1) reduce bias and 2) improve statistical efficiency.
In our latest work we investigated the effect of antiseizure medication prescribing/dispensation in pregnancy on offspring neurodevelopmental outcomes using over 3 million pregnancies from the UK and Sweden. Article out now in Nature Comms: nature.com/articles/s41...
November 21, 2024 at 10:37 AM
In our latest work we investigated the effect of antiseizure medication prescribing/dispensation in pregnancy on offspring neurodevelopmental outcomes using over 3 million pregnancies from the UK and Sweden. Article out now in Nature Comms: nature.com/articles/s41...
We are running our short course on Advanced Multiple Imputation Methods to Deal with Missing data this December (5th and 6th).
link for further info: tinyurl.com/ybu982ru
link for further info: tinyurl.com/ybu982ru
Advanced Multiple Imputation Methods to Deal with Missing Data
Multiple imputation is a principled approach to account for missing data in analyses where valid results depends on careful construction of the imputation model. The potential for misspecification of ...
tinyurl.com
October 7, 2024 at 10:06 AM
We are running our short course on Advanced Multiple Imputation Methods to Deal with Missing data this December (5th and 6th).
link for further info: tinyurl.com/ybu982ru
link for further info: tinyurl.com/ybu982ru