Computational Identifiability
Summary
Researchers from New York University introduce "Computational Identifiability," a novel framework that redefines identifiability as a finite computational search for an empirical estimator, contrasting it with traditional theoretical identifiability that assumes idealized conditions like infinite data. This approach considers a target query identifiable if an estimator can be found empirically within a specified error tolerance, conditional on a prior distribution over parameters and the search procedure. The framework leverages a meta-prior over structural causal models (SCMs) and a hypothesis space of estimators, operating with finite sample sizes, a desired error tolerance ε, and a confidence bound δ. Experiments demonstrate its utility in practical scenarios, including identification with small finite samples, ambiguous graphical criteria, mixed observational-interventional data, and counterfactual estimands. Code is available at https://github.com/lbynum/metadentify.
Key takeaway
For causal inference practitioners evaluating the feasibility of estimating effects with finite, noisy data, this framework provides an actionable approach. You should consider using computational identifiability to empirically determine if a target parameter is estimable within a desired error tolerance, rather than relying solely on theoretical guarantees. This method helps in selecting optimal adjustment sets, assessing transportability with mixed data, and understanding the practical limits of CATE versus ITE estimation.
Key insights
Computational identifiability reframes identification as a finite, empirical search for an estimator within specified error bounds.
Principles
- Identifiability can be conditional on a prior over SCMs and a hypothesis space.
- Approximation within an ε margin is sufficient, not perfect prediction.
- Computational identifiability can have non-monotonic relationships with dataset size.
Method
Meta-learn an estimator φ from observations and query points to causal query values, using a joint causal-query-mixture distribution.
In practice
- Distinguish optimal adjustment sets when theoretical criteria are ambiguous.
- Evaluate identifiability with mixed observational-interventional data for transportability.
- Compare CATE vs. ITE identification under finite samples and noise.
Topics
- Computational Identifiability
- Causal Inference
- Meta-learning
- Structural Causal Models
- Causal Effect Estimation
- Finite Sample Analysis
Code references
Best for: Research Scientist, AI Scientist, Machine Learning Engineer, Data Scientist
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Editorial summary, takeaway, and curation by AIssential. Original article published by stat.ML updates on arXiv.org.