Miguel Hernan
@miguelhernan.org
https://miguelhernan.org/
Using health data to learn what works.
Making #causalinference less casual.
Director, @causalab.bsky.social
Professor, @hsph.harvard.edu
Methods Editor, Annals of Internal Medicine @annalsofim.bsky.social
Using health data to learn what works.
Making #causalinference less casual.
Director, @causalab.bsky.social
Professor, @hsph.harvard.edu
Methods Editor, Annals of Internal Medicine @annalsofim.bsky.social
Pinned
Miguel Hernan
@miguelhernan.org
· Dec 23
Upgrade your #causalinference arsenal.
A revision of our book "Causal Inference: What If" is available at miguelhernan.org/whatifbook
Thanks to everyone who suggested improvements, reported typos, and proposed new citations and material.
Enjoy the #WhatIfBook plus code and data. Also, it's free.
A revision of our book "Causal Inference: What If" is available at miguelhernan.org/whatifbook
Thanks to everyone who suggested improvements, reported typos, and proposed new citations and material.
Enjoy the #WhatIfBook plus code and data. Also, it's free.
Reposted by Miguel Hernan
You're invited! ✉️
20th Kolokotrones Symposium: “Acetaminophen During Pregnancy and Autism: What Does Causal Inference Take?"
Details in comments. In-person limited to Harvard ID holders due to space restrictions. Online attendance free & public.
Register:
www.eventbrite.com/e/acetaminop...
20th Kolokotrones Symposium: “Acetaminophen During Pregnancy and Autism: What Does Causal Inference Take?"
Details in comments. In-person limited to Harvard ID holders due to space restrictions. Online attendance free & public.
Register:
www.eventbrite.com/e/acetaminop...
October 9, 2025 at 5:51 PM
You're invited! ✉️
20th Kolokotrones Symposium: “Acetaminophen During Pregnancy and Autism: What Does Causal Inference Take?"
Details in comments. In-person limited to Harvard ID holders due to space restrictions. Online attendance free & public.
Register:
www.eventbrite.com/e/acetaminop...
20th Kolokotrones Symposium: “Acetaminophen During Pregnancy and Autism: What Does Causal Inference Take?"
Details in comments. In-person limited to Harvard ID holders due to space restrictions. Online attendance free & public.
Register:
www.eventbrite.com/e/acetaminop...
Reposted by Miguel Hernan
Free Causal Inference Consulting Available at Harvard T.H. Chan School of Public Health!
Take advantage of expert advice for your research projects. Learn more and help spread the word! :)
Take advantage of expert advice for your research projects. Learn more and help spread the word! :)
Fall applications are OPEN for CAUSALab Clinics!
Free #causalinference consulting open to Boston-based, junior clinical investigators. Postdoc fellows provide guidance pertaining to #studydesign, data analysis and results for works in progress.
Learn more & apply:
hsph.harvard.edu/research/cau...
Free #causalinference consulting open to Boston-based, junior clinical investigators. Postdoc fellows provide guidance pertaining to #studydesign, data analysis and results for works in progress.
Learn more & apply:
hsph.harvard.edu/research/cau...
September 4, 2025 at 3:54 PM
Free Causal Inference Consulting Available at Harvard T.H. Chan School of Public Health!
Take advantage of expert advice for your research projects. Learn more and help spread the word! :)
Take advantage of expert advice for your research projects. Learn more and help spread the word! :)
When using observational data for #causalinference, the choice isn’t between emulating or not emulating a #TargetTrial, but between reporting or not reporting the target trial that we are emulating.
For those who prefer to be explicit about what they do, we have developed the TARGET Statement 👇
For those who prefer to be explicit about what they do, we have developed the TARGET Statement 👇
🎯 TARGET Guideline published 🎉
TARGET is a reporting guideline for observational studies of interventions that use the target trial framework.
Over 3 years the @TARGETGuideline was rigorously developed and was co-published today in @jama.com & @bmj.com
doi.org/10.1001/jama.2025.13350
#episky
TARGET is a reporting guideline for observational studies of interventions that use the target trial framework.
Over 3 years the @TARGETGuideline was rigorously developed and was co-published today in @jama.com & @bmj.com
doi.org/10.1001/jama.2025.13350
#episky
September 3, 2025 at 10:30 PM
When using observational data for #causalinference, the choice isn’t between emulating or not emulating a #TargetTrial, but between reporting or not reporting the target trial that we are emulating.
For those who prefer to be explicit about what they do, we have developed the TARGET Statement 👇
For those who prefer to be explicit about what they do, we have developed the TARGET Statement 👇
Reposted by Miguel Hernan
SER 2025 @societyforepi.bsky.social included a session spotlighting James M. Robins⭐
"Celebrating James M. Robins Contributions to Epidemiology" explored Robins' impact, including his landmark 1986 paper. It concluded with his comments on progress still to come in #causalinference research.
"Celebrating James M. Robins Contributions to Epidemiology" explored Robins' impact, including his landmark 1986 paper. It concluded with his comments on progress still to come in #causalinference research.
July 8, 2025 at 2:53 PM
SER 2025 @societyforepi.bsky.social included a session spotlighting James M. Robins⭐
"Celebrating James M. Robins Contributions to Epidemiology" explored Robins' impact, including his landmark 1986 paper. It concluded with his comments on progress still to come in #causalinference research.
"Celebrating James M. Robins Contributions to Epidemiology" explored Robins' impact, including his landmark 1986 paper. It concluded with his comments on progress still to come in #causalinference research.
Reposted by Miguel Hernan
New publication: Effect of colonoscopy screening on risks of colorectal cancer and related death: instrumental variable estimation of per-protocol effects now in the European Journal of Epidemiology
➡️ Read here: link.springer.com/article/10.1...
#cancer #screening #colorectal
➡️ Read here: link.springer.com/article/10.1...
#cancer #screening #colorectal
Effect of colonoscopy screening on risks of colorectal cancer and related death: instrumental variable estimation of per-protocol effects - European Journal of Epidemiology
Background We recently reported per-protocol estimates of colonoscopy screening on colorectal cancer incidence and mortality in NordICC, a large-scale randomized trial. Our results may be affected by ...
link.springer.com
May 23, 2025 at 2:26 PM
New publication: Effect of colonoscopy screening on risks of colorectal cancer and related death: instrumental variable estimation of per-protocol effects now in the European Journal of Epidemiology
➡️ Read here: link.springer.com/article/10.1...
#cancer #screening #colorectal
➡️ Read here: link.springer.com/article/10.1...
#cancer #screening #colorectal
Reposted by Miguel Hernan
See you in Madrid?
CAUSALab is partnering w/ @cemfi.es for the course, Causal Inference for Health and Social Scientists.
📆 Aug 25-29, 2025
Taught by @miguelhernan.org, CEMFI course introduces 2 step causal framework for experimental & non-experimental data.
www.cemfi.es/programs/css...
CAUSALab is partnering w/ @cemfi.es for the course, Causal Inference for Health and Social Scientists.
📆 Aug 25-29, 2025
Taught by @miguelhernan.org, CEMFI course introduces 2 step causal framework for experimental & non-experimental data.
www.cemfi.es/programs/css...
May 22, 2025 at 8:45 PM
See you in Madrid?
CAUSALab is partnering w/ @cemfi.es for the course, Causal Inference for Health and Social Scientists.
📆 Aug 25-29, 2025
Taught by @miguelhernan.org, CEMFI course introduces 2 step causal framework for experimental & non-experimental data.
www.cemfi.es/programs/css...
CAUSALab is partnering w/ @cemfi.es for the course, Causal Inference for Health and Social Scientists.
📆 Aug 25-29, 2025
Taught by @miguelhernan.org, CEMFI course introduces 2 step causal framework for experimental & non-experimental data.
www.cemfi.es/programs/css...
If you're wondering about differences between publicly-funded research in non-profit universities and
privately-funded research in for-profit companies, watch this:
www.youtube.com/watch?v=Ar0z...
The topic is the "de-extinction of the dire wolf", but the message applies beyond it. (Think "AI".)
privately-funded research in for-profit companies, watch this:
www.youtube.com/watch?v=Ar0z...
The topic is the "de-extinction of the dire wolf", but the message applies beyond it. (Think "AI".)
They Didn't Make Dire Wolves, They Made Something…Else
YouTube video by hankschannel
www.youtube.com
April 24, 2025 at 2:40 PM
If you're wondering about differences between publicly-funded research in non-profit universities and
privately-funded research in for-profit companies, watch this:
www.youtube.com/watch?v=Ar0z...
The topic is the "de-extinction of the dire wolf", but the message applies beyond it. (Think "AI".)
privately-funded research in for-profit companies, watch this:
www.youtube.com/watch?v=Ar0z...
The topic is the "de-extinction of the dire wolf", but the message applies beyond it. (Think "AI".)
Barbra Dickerman, @joy-shi.bsky.social, and I have a new online course for anyone who wants to learn the basics of confounding adjustment for time-fixed treatments.
A must if you are considering CAUSALab's "Advanced Confounding Adjustment" course for time-varying treatments in the Summer.
A must if you are considering CAUSALab's "Advanced Confounding Adjustment" course for time-varying treatments in the Summer.
NEW in 2025:
⭐ Fundamentals of Confounding Adjustment (FCA)
Learn confounding adjustment in time-fixed settings & build a foundation for advanced methods. Self-paced course w/ video lectures & hands-on exercises.
Ready to join our FCA classroom? Register now:
causalab.hsph.harvard.edu/courses/
⭐ Fundamentals of Confounding Adjustment (FCA)
Learn confounding adjustment in time-fixed settings & build a foundation for advanced methods. Self-paced course w/ video lectures & hands-on exercises.
Ready to join our FCA classroom? Register now:
causalab.hsph.harvard.edu/courses/
April 2, 2025 at 9:10 PM
Barbra Dickerman, @joy-shi.bsky.social, and I have a new online course for anyone who wants to learn the basics of confounding adjustment for time-fixed treatments.
A must if you are considering CAUSALab's "Advanced Confounding Adjustment" course for time-varying treatments in the Summer.
A must if you are considering CAUSALab's "Advanced Confounding Adjustment" course for time-varying treatments in the Summer.
Reposted by Miguel Hernan
Join us on Wednesday, March 5th at 1:00pm EST for the Department's seminar series with Miguel Hernan speaking on "How to make people immortal and why it is not a good idea: Improving the causal analyses of healthcare databases"
➡️ Go to event page to register: hsph.harvard.edu/epidemiology...
➡️ Go to event page to register: hsph.harvard.edu/epidemiology...
February 26, 2025 at 7:09 PM
Join us on Wednesday, March 5th at 1:00pm EST for the Department's seminar series with Miguel Hernan speaking on "How to make people immortal and why it is not a good idea: Improving the causal analyses of healthcare databases"
➡️ Go to event page to register: hsph.harvard.edu/epidemiology...
➡️ Go to event page to register: hsph.harvard.edu/epidemiology...
1/ When using observational data for #causalinference, emulating a target trial helps solve some problems... but not all problems.
In a new paper, we explain why and when the #TargetTrial framework is helpful.
www.acpjournals.org/doi/10.7326/...
Joint work with my colleagues @causalab.bsky.social
In a new paper, we explain why and when the #TargetTrial framework is helpful.
www.acpjournals.org/doi/10.7326/...
Joint work with my colleagues @causalab.bsky.social
February 18, 2025 at 1:08 PM
1/ When using observational data for #causalinference, emulating a target trial helps solve some problems... but not all problems.
In a new paper, we explain why and when the #TargetTrial framework is helpful.
www.acpjournals.org/doi/10.7326/...
Joint work with my colleagues @causalab.bsky.social
In a new paper, we explain why and when the #TargetTrial framework is helpful.
www.acpjournals.org/doi/10.7326/...
Joint work with my colleagues @causalab.bsky.social
1/
If you were taught to test for proportional hazards, talk to your teacher.
The proportional hazards assumption is implausible in most #randomized and #observational studies because the hazard ratios aren't expected to be constant during the follow-up. So "testing" is futile.
But there is more 👇
If you were taught to test for proportional hazards, talk to your teacher.
The proportional hazards assumption is implausible in most #randomized and #observational studies because the hazard ratios aren't expected to be constant during the follow-up. So "testing" is futile.
But there is more 👇
February 3, 2025 at 2:51 PM
1/
If you were taught to test for proportional hazards, talk to your teacher.
The proportional hazards assumption is implausible in most #randomized and #observational studies because the hazard ratios aren't expected to be constant during the follow-up. So "testing" is futile.
But there is more 👇
If you were taught to test for proportional hazards, talk to your teacher.
The proportional hazards assumption is implausible in most #randomized and #observational studies because the hazard ratios aren't expected to be constant during the follow-up. So "testing" is futile.
But there is more 👇
1/
That "immortal time" is so frequent in survival analyses for #causalinference is fascinating.
Because "immortal time" doesn't exist in the data, *we* create it when misanalyzing the data.
Our new paper pubmed.ncbi.nlm.nih.gov/39494894/ summarizes why immortal time arises & how to prevent it.
That "immortal time" is so frequent in survival analyses for #causalinference is fascinating.
Because "immortal time" doesn't exist in the data, *we* create it when misanalyzing the data.
Our new paper pubmed.ncbi.nlm.nih.gov/39494894/ summarizes why immortal time arises & how to prevent it.
January 6, 2025 at 4:41 PM
1/
That "immortal time" is so frequent in survival analyses for #causalinference is fascinating.
Because "immortal time" doesn't exist in the data, *we* create it when misanalyzing the data.
Our new paper pubmed.ncbi.nlm.nih.gov/39494894/ summarizes why immortal time arises & how to prevent it.
That "immortal time" is so frequent in survival analyses for #causalinference is fascinating.
Because "immortal time" doesn't exist in the data, *we* create it when misanalyzing the data.
Our new paper pubmed.ncbi.nlm.nih.gov/39494894/ summarizes why immortal time arises & how to prevent it.
Upgrade your #causalinference arsenal.
A revision of our book "Causal Inference: What If" is available at miguelhernan.org/whatifbook
Thanks to everyone who suggested improvements, reported typos, and proposed new citations and material.
Enjoy the #WhatIfBook plus code and data. Also, it's free.
A revision of our book "Causal Inference: What If" is available at miguelhernan.org/whatifbook
Thanks to everyone who suggested improvements, reported typos, and proposed new citations and material.
Enjoy the #WhatIfBook plus code and data. Also, it's free.
December 23, 2024 at 9:28 AM
Upgrade your #causalinference arsenal.
A revision of our book "Causal Inference: What If" is available at miguelhernan.org/whatifbook
Thanks to everyone who suggested improvements, reported typos, and proposed new citations and material.
Enjoy the #WhatIfBook plus code and data. Also, it's free.
A revision of our book "Causal Inference: What If" is available at miguelhernan.org/whatifbook
Thanks to everyone who suggested improvements, reported typos, and proposed new citations and material.
Enjoy the #WhatIfBook plus code and data. Also, it's free.
Does #randomization ensures balance of risk factors between groups? Consider this:
In Denmark 860 individuals were randomly allocated to either intervention or control. Individuals were unaware of their allocation. No intervention took place. Mortality was higher in the intervention group (p=0.003)
In Denmark 860 individuals were randomly allocated to either intervention or control. Individuals were unaware of their allocation. No intervention took place. Mortality was higher in the intervention group (p=0.003)
November 26, 2024 at 1:38 PM
Does #randomization ensures balance of risk factors between groups? Consider this:
In Denmark 860 individuals were randomly allocated to either intervention or control. Individuals were unaware of their allocation. No intervention took place. Mortality was higher in the intervention group (p=0.003)
In Denmark 860 individuals were randomly allocated to either intervention or control. Individuals were unaware of their allocation. No intervention took place. Mortality was higher in the intervention group (p=0.003)
It's always a good time to remember Brandolini's principle
@ziobrando.bsky.social
@ziobrando.bsky.social
November 20, 2024 at 5:34 PM
It's always a good time to remember Brandolini's principle
@ziobrando.bsky.social
@ziobrando.bsky.social
Join us today!
Join us tomorrow, Tues 10/29 3:00pm ET for the Center for Suicide Research and Prevention (CSRP) & @causalab.bsky.social's Suicide Research Colloquium.
This month's topic - #causalinference & #suicideprevention.
Attend in-person: bit.ly/SRCsession6
Attend online: bit.ly/src_zoom
This month's topic - #causalinference & #suicideprevention.
Attend in-person: bit.ly/SRCsession6
Attend online: bit.ly/src_zoom
October 29, 2024 at 3:27 PM
Join us today!
Reposted by Miguel Hernan
I enjoyed 'The Hazards of Hazard Ratios' by @miguelhernan.bsky.social!
journals.lww.com/epidem/fullt...
journals.lww.com/epidem/fullt...
The Hazards of Hazard Ratios : Epidemiology
An abstract is unavailable.
journals.lww.com
October 13, 2024 at 8:05 AM
I enjoyed 'The Hazards of Hazard Ratios' by @miguelhernan.bsky.social!
journals.lww.com/epidem/fullt...
journals.lww.com/epidem/fullt...
Reposted by Miguel Hernan
Congrats to Roger Logan on his retirement!
Roger has worked as a CAUSALab Senior Research Scientist @harvardchanschool.bsky.social for 23 years. He has been a valuable team member & made major contributions to #causalinference research.
Wishing Roger all the best in this new chapter! #publichealth
Roger has worked as a CAUSALab Senior Research Scientist @harvardchanschool.bsky.social for 23 years. He has been a valuable team member & made major contributions to #causalinference research.
Wishing Roger all the best in this new chapter! #publichealth
October 2, 2024 at 6:17 PM
Congrats to Roger Logan on his retirement!
Roger has worked as a CAUSALab Senior Research Scientist @harvardchanschool.bsky.social for 23 years. He has been a valuable team member & made major contributions to #causalinference research.
Wishing Roger all the best in this new chapter! #publichealth
Roger has worked as a CAUSALab Senior Research Scientist @harvardchanschool.bsky.social for 23 years. He has been a valuable team member & made major contributions to #causalinference research.
Wishing Roger all the best in this new chapter! #publichealth
Reposted by Miguel Hernan
Really enjoyed @miguelhernan.bsky.social's talk on the promises and limitations of AI for health data research at the #WCE2024!
A fair and critical dose of reality that the wider health research sphere desparately needs to hear!
#EpiSky
A fair and critical dose of reality that the wider health research sphere desparately needs to hear!
#EpiSky
September 27, 2024 at 1:45 PM
Really enjoyed @miguelhernan.bsky.social's talk on the promises and limitations of AI for health data research at the #WCE2024!
A fair and critical dose of reality that the wider health research sphere desparately needs to hear!
#EpiSky
A fair and critical dose of reality that the wider health research sphere desparately needs to hear!
#EpiSky
Reposted by Miguel Hernan
New research published in Annals of Internal Medicine challenges past scholarship on metformin.
CAUSALab collaborator Yu-Han Chiu identified no increased risk for childbirth with major birth defects when compared w/ women who discontinued the drug.
CNN article: www.cnn.com/2024/06/17/h...
CAUSALab collaborator Yu-Han Chiu identified no increased risk for childbirth with major birth defects when compared w/ women who discontinued the drug.
CNN article: www.cnn.com/2024/06/17/h...
June 24, 2024 at 6:56 PM
New research published in Annals of Internal Medicine challenges past scholarship on metformin.
CAUSALab collaborator Yu-Han Chiu identified no increased risk for childbirth with major birth defects when compared w/ women who discontinued the drug.
CNN article: www.cnn.com/2024/06/17/h...
CAUSALab collaborator Yu-Han Chiu identified no increased risk for childbirth with major birth defects when compared w/ women who discontinued the drug.
CNN article: www.cnn.com/2024/06/17/h...
This week I discussed methods for health technology assessment at HTAi. My main point:
"Observational data (#RWD) can often be used to emulate a #TargetTrial, but we need more research to characterize questions that can only be answered by randomized trials."
Let's learn the limits of #RWE.
"Observational data (#RWD) can often be used to emulate a #TargetTrial, but we need more research to characterize questions that can only be answered by randomized trials."
Let's learn the limits of #RWE.
June 23, 2024 at 3:43 PM
This week I discussed methods for health technology assessment at HTAi. My main point:
"Observational data (#RWD) can often be used to emulate a #TargetTrial, but we need more research to characterize questions that can only be answered by randomized trials."
Let's learn the limits of #RWE.
"Observational data (#RWD) can often be used to emulate a #TargetTrial, but we need more research to characterize questions that can only be answered by randomized trials."
Let's learn the limits of #RWE.
Did you know that the LATE estimator was independently described in 1994 by
Imbens & Angrist in Econometrica
and
Baker & Lindeman in Statistics in Medicine?
onlinelibrary.wiley.com/doi/10.1002/...
A delightful historical overview of LATE is now available www.tandfonline.com/doi/full/10....
Imbens & Angrist in Econometrica
and
Baker & Lindeman in Statistics in Medicine?
onlinelibrary.wiley.com/doi/10.1002/...
A delightful historical overview of LATE is now available www.tandfonline.com/doi/full/10....
June 11, 2024 at 12:41 PM
Did you know that the LATE estimator was independently described in 1994 by
Imbens & Angrist in Econometrica
and
Baker & Lindeman in Statistics in Medicine?
onlinelibrary.wiley.com/doi/10.1002/...
A delightful historical overview of LATE is now available www.tandfonline.com/doi/full/10....
Imbens & Angrist in Econometrica
and
Baker & Lindeman in Statistics in Medicine?
onlinelibrary.wiley.com/doi/10.1002/...
A delightful historical overview of LATE is now available www.tandfonline.com/doi/full/10....
With #TargetTrial emulation becoming increasingly popular, it's important to understand what it can and can't do.
In this podcast I discuss how target trial emulation can improve causal inference from observational data and extend inferences from randomized trials
edhub.ama-assn.org/jn-learning/...
In this podcast I discuss how target trial emulation can improve causal inference from observational data and extend inferences from randomized trials
edhub.ama-assn.org/jn-learning/...
Target Trial Emulation for Causal Inference From Observational Data With Dr Hernán
Miguel A. Hernán, MD, DrPH, professor of epidemiology, Harvard T.H. Chan School of Public Health, discusses Target Trial Emulation: A Framework for Causal Inference From Observational Data with JAMA Statistical Editor Roger J. Lewis, MD, PhD.
edhub.ama-assn.org
May 18, 2024 at 8:42 PM
With #TargetTrial emulation becoming increasingly popular, it's important to understand what it can and can't do.
In this podcast I discuss how target trial emulation can improve causal inference from observational data and extend inferences from randomized trials
edhub.ama-assn.org/jn-learning/...
In this podcast I discuss how target trial emulation can improve causal inference from observational data and extend inferences from randomized trials
edhub.ama-assn.org/jn-learning/...
Reposted by Miguel Hernan
First FEP-CAUSAL collab paper is out in AJE!
pubmed.ncbi.nlm.nih.gov/38576166/
Target trial emulation findings support aripiprazole & paliperidone as first-line therapy in first episode psychosis treatment.
Led by CAUSALab researchers Alejandro Szmulewicz & @miguelhernan.bsky.social.
pubmed.ncbi.nlm.nih.gov/38576166/
Target trial emulation findings support aripiprazole & paliperidone as first-line therapy in first episode psychosis treatment.
Led by CAUSALab researchers Alejandro Szmulewicz & @miguelhernan.bsky.social.
April 16, 2024 at 4:07 PM
First FEP-CAUSAL collab paper is out in AJE!
pubmed.ncbi.nlm.nih.gov/38576166/
Target trial emulation findings support aripiprazole & paliperidone as first-line therapy in first episode psychosis treatment.
Led by CAUSALab researchers Alejandro Szmulewicz & @miguelhernan.bsky.social.
pubmed.ncbi.nlm.nih.gov/38576166/
Target trial emulation findings support aripiprazole & paliperidone as first-line therapy in first episode psychosis treatment.
Led by CAUSALab researchers Alejandro Szmulewicz & @miguelhernan.bsky.social.