🤖 AI Summary
This work addresses the challenge of determining causal effect identifiability in linear structural causal models with latent confounding, a problem traditionally hindered by the double-exponential computational complexity of Gröbner basis methods. The authors propose a novel symbolic computation algorithm that, for the first time, decides rational identifiability of causal effects in quasipolynomial time and efficiently computes the lowest-degree identification formula under a given maximum degree constraint. By integrating techniques from algebraic geometry with causal inference theory, the method substantially enhances algorithmic scalability and practical applicability, thereby overcoming a longstanding computational bottleneck in the field.
📝 Abstract
Determining identifiability of causal effects from observational data under latent confounding is a central challenge in causal inference. For linear structural causal models, identifiability of causal effects is decidable through symbolic computation. However, standard approaches based on Gröbner bases become computationally infeasible beyond small settings due to their doubly exponential complexity. In this work, we study how to practically use symbolic computation for deciding rational identifiability. In particular, we present an efficient algorithm that provably finds the lowest degree identifying formulas. For a causal effect of interest, if there exists an identification formula of a prespecified maximal degree, our algorithm returns such a formula in quasi-polynomial time.