Amortized Inference for Correlated Discrete Choice Models via Equivariant Neural Networks
Summary
A novel amortized inference approach utilizes a neural network emulator to rapidly approximate choice probabilities for discrete choice models, including those with correlated errors like Multinomial Probit (MNP). This method addresses the computational demands of MNP models, which lack closed-form solutions and typically rely on slow GHK simulation. The proposed architecture incorporates group-theoretic foundations, enforcing invariance properties and achieving universal approximation. Employing Sobolev training, the emulator learns both choice probabilities and their derivatives, enabling fast likelihood and gradient computations. Simulations demonstrate significant gains in accuracy and speed over the GHK simulator for MNP models with 3, 5, and 10 alternatives. Training for K=3, 5, and 10 took 2.1, 4.6, and 16.6 hours, respectively, with multi-K training also proving effective.
Key takeaway
For Machine Learning Engineers or Econometricians developing discrete choice models, this amortized inference framework offers a compelling solution to the computational bottlenecks of models with correlated errors. You can now efficiently estimate complex models like Multinomial Probit or correlated Gumbel, which previously required slow simulation methods. Integrate this pre-trained emulator to accelerate likelihood and gradient computations, enabling faster maximum likelihood or Bayesian inference. This allows for exploring richer, theoretically grounded choice behaviors without sacrificing interpretability, provided your application's input distribution aligns with the emulator's training data.
Key insights
An equivariant neural network emulator enables rapid, accurate estimation of discrete choice probabilities for models with complex correlated errors.
Principles
- Discrete choice models exhibit inherent location, scale, and permutation invariances.
- Amortized inference pre-computes complex probabilities via one-time training.
- Sobolev training ensures accurate gradient approximation for model fitting.
Method
Train a DeepSet-based neural network emulator on simulated data, using preprocessing to enforce invariance and Sobolev training to match choice probabilities and their derivatives.
In practice
- Substitute emulator evaluations for GHK simulations in MNP models.
- Extend to correlated Gumbel or multivariate-t error distributions.
- Integrate into gradient-based MLE or Hamiltonian Monte Carlo workflows.
Topics
- Amortized Inference
- Discrete Choice Models
- Neural Network Emulators
- Multinomial Probit
- Sobolev Training
- Permutation Equivariance
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Editorial summary, takeaway, and curation by AIssential. Original article published by cs.LG updates on arXiv.org.