Questions tagged [collider]
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11 questions
1 vote
0 answers
41 views
Inverse Probability of Weighting in Directed acyclic graph for a binary collider as a selection bias
For a confounder, like the following figure, it is commonly suggested that use of the Inverse Probability of Weighting can remove the path from confounder to exposure so that it removes the backdoor ...
- 11
1 vote
1 answer
91 views
Causality - Can adding predictors unblock causal effects?
My question pertains to the following empirical situation. You have a bivariate model (e.g. regression), and you find no effect of $X$ on $Y$. Then you add a covariate in your model, $Z$, and now you ...
- 921
1 vote
1 answer
240 views
When does Dose Response Function estimation work better than simple regression?
I have been recently asked what is the difference between a Dose Response Function (DRF) estimation (as the one proposed in this link and this paper) and a statistical regression method. I therefore ...
- 460
6 votes
2 answers
987 views
Why does controlling for a collider open a path, while controlling for a confounder closes a path, if there are relations to third variable for both?
Collider bias occurs when there is no association between X and Y but when a third variable which is caused by both X and Y is controlled for, this "opens a path" between X and Y and leads ...
- 1,464
2 votes
1 answer
146 views
Should we adjust for this variable?
Four variables $X$, $Y$, $A$, and $B$ are assumed to have relationships as in the following diagram: Here, $X$ is the predictor and $Y$ is the outcome variable. Suppose that the research interest is ...
- 2,831
2 votes
1 answer
90 views
May unobserved variable confound or create open backdoor paths, why didn't controlling for the collider O make bad?
Is the U, the unobserved creating an open backdoor path or confounding? Why condition on the collider Occupation good here?
user384464
4 votes
2 answers
357 views
According to DAG theory, why controlling for this variable doesn't close the backdoor path opened by controlling for the collider?
I have made the following model in DAGitty: Where $X_2$ is controlled for. DAGitty says: The total effect cannot be estimated due to adjustment for an intermediate or a descendant of an intermediate....
- 3,403
0 votes
1 answer
138 views
Instrumental variable identifiability in a linear setting in the presence of unobserved confounders
Long story short, I'm seeing in the literature that linear instrumental variables models are identifiable, even in the presence of unobserved confounders. The unobserved confounding aspect befuddles ...
- 367
0 votes
1 answer
149 views
Biased sample same like conditioning on a collider?
I am studying chapter 5 "The many variables & the spurious waffles" of the book Rethinking and trying to answer the following question: How is biased sample like conditioning on a ...
- 429
1 vote
1 answer
148 views
Conditioning on a future (post intervention/treatment and post outcome) event in a causal diagram?
My team is conducting a pre/post-intervention comparison of health outcomes in treatment and control groups, and the question came up whether it's a good idea condition/match on a deceased flag for ...
- 6,644
4 votes
1 answer
187 views
Should pre-intervention outcome variable Y0 be excluded from counterfactual model based on causal diagram?
Based on the causal diagram below, where: Y1 is the outcome in the post-intervention period, Y0 is the pre-intervention outcome, X is a Yes/No healthcare intervention, and Z1 & Z2 represent ...
- 6,644