Iván Díaz
@idiaz.bsky.social
1.2K followers 230 following 57 posts
Statistician. Associate prof. at NYU Grossman Department of Population Health. Causal inference, machine learning, and semiparametric estimation. https://idiazst.github.io/website/
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Reposted by Iván Díaz
herbps10.bsky.social
New preprint out on a way to handle structural and practical violations of the overlap (also known as positivity) assumption in causal inference -- as long as the outcome is bounded, we derive simple partial identification bounds on the ATE. With @alecmcclean.bsky.social and @idiaz.bsky.social
Non-overlap Average Treatment Effect Bounds by Herbert P. Susmann, Alec McClean, and Iván Díaz
Reposted by Iván Díaz
alxndrmlk.bsky.social
He did it before Double Machine Learning

I met with professor Mark van der Laan because I think his work is pretty incredible and it sometimes feels like a secret that only a few people know about, especially in industry.

1/

#CausalSky #StatSky #CausalInference
idiaz.bsky.social
But I do agree that the addendum is progress from the previous state of things!
idiaz.bsky.social
But more seriously, the addition would have been a sentence and a couple of references, not a complete framework, which already exists.
idiaz.bsky.social
The better analogy is a bus that drops you off midway to your destination, not even in a bus stop, and steals your phone so you can’t get home 😉
idiaz.bsky.social
I think the addendum fell short and should have described a need and approaches to mathematically define and identify estimands.
idiaz.bsky.social
Thanks for sharing. Tangential to the thread but I have to say that I disagree with the statement of the abstract that causal inference estimands correspond to an effect in an ideal trial. Many valid scientific questions are expressed in terms of parameters that cannot be identified in trials!
idiaz.bsky.social
What I do not follow about both TTE and addendum is why reinvent the wheel. I get it if it is about communicating to new audiences, but not if they are presented as new methods when they are so clearly inferior to what's already out there.
bsky.app/profile/idia...
idiaz.bsky.social
TTE is certainly useful (I use it). But it is not a replacement for formal causal models + causal estimands + identification + optimal estimation etc. I recommend reading Maya Petersen and colleagues' papers on the "roadmap for causal inference."
idiaz.bsky.social
TTE is certainly useful (I use it). But it is not a replacement for formal causal models + causal estimands + identification + optimal estimation etc. I recommend reading Maya Petersen and colleagues' papers on the "roadmap for causal inference."
idiaz.bsky.social
Presenting TTEs as a method rather than as a communication tool had the unintended consequence of folks slapping the moniker in studies as a quality signifier without doing the actual leg work required to address the issues, discussing them, or even understanding them.
idiaz.bsky.social
Right, IMO target trials are a great *communication tool* to talk with folks who do not have in-depth causal inference training (hence their success), but to really understand the issues one has to rely on standard theory (causal models, identification, estimands, optimal estimation, etc.)
idiaz.bsky.social
Curious to hear if the gripes are substantive or if they are attribution-type (e.g., causal inference was using estimands long before the addendum).
idiaz.bsky.social
It should be telling that it is the field of CI that has given folks the tools to understand the conditions under which observational studies deliver causal effects. You may argue whether those conditions are ever achievable, but criticizing CI for achieving its goal seems silly.
idiaz.bsky.social
Underlying this there is a valid and worrisome criticism of causal inference in practice, but most comments criticizing CI as a field miss the fact that “x methodology is being abused in practice” can be correctly said about almost anything.
statsepi.bsky.social
We didn't randomize, and there was no allocation concealment or blinding, and we can't really be sure what intervention they got or how the outcomes were measured, but we emulated a trial by drawing a DAG.
idiaz.bsky.social
Clinician: How do I make sure Y(a) is independent of A conditional on covariates

Statistician: You measure all common causes of A and Y…

🤷🏻
idiaz.bsky.social
This is why I prefer causal assumptions in terms of exogenous vars in structural causal models rather potential outcomes. Sure, the former is often mathematically stronger, but the latter is inscrutable by subject matter experts.
p-hunermund.com
💡A new paper by Elias Bareinboim and Drago Plecko underscores the intractability of ignorability assumptions commonly invoked in the potential outcomes framework, explains why structural causal models—explicitly grounded in well-defined causal mechanisms—are far easier to interpret. 1/2
idiaz.bsky.social
I think missing data is a CI problem (counterfactual is "would have observed the data") but not the opposite. E.g., recasting mediation analyses etc as a missing data problems seems contrived.
idiaz.bsky.social
Cheap non alcoholic cava in a tetra pack container. How come the outcomes have to be “potential”?
idiaz.bsky.social
At some point we’ll have to give these guys some agency 😉
idiaz.bsky.social
Re: the OP, it also seems right to me that stats should focus on the properties of estimators, but the stubborn rejection of the language that links stats to science (CI) by some “trad” statisticians seems very odd to me
idiaz.bsky.social
On this, I agree with Pearl and others who have emphasized that estimators aren’t causal. A causal estimand equals a statistical estimand (usually) under assumptions; estimators target statistical estimando which may or may not have a causal interpretation.
Reposted by Iván Díaz
alecmcclean.bsky.social
Excited to present on Thursday @eurocim.bsky.social on new work with @idiaz.bsky.social on (smooth) trimming with longitudinal data!

"Longitudinal trimming and smooth trimming with flip and S-flip interventions"

Prelim draft: alecmcclean.github.io/files/LSTTEs...