Causal Discovery Algorithm Selection Meta-Learner

A meta-learning system that predicts the top-3 best causal discovery algorithms for any discrete observational dataset, based on dataset meta-features.

🎯 What it Does

Given a new discrete dataset (pandas DataFrame), the system:

1. Extracts 34 meta-features (entropy, mutual information, chi² statistics, CI test probes, etc.)
2. Predicts normalized SHD for each of 9 algorithms via trained models
3. Ranks and returns the top-3 algorithms expected to produce the most accurate CPDAG

📊 Performance (Leave-One-Network-Out Cross-Validation)

Best Model: Pairwise-GBM Ranking

Model Comparison (178 configs, 14 networks + augmented)

Progression

🧪 Algorithm Pool (9 algorithms)

🔬 Key Insight: Dependency Parsing Connection

This project was inspired by a structural parallel between NLP dependency parsing and causal discovery:

• Both predict directed graphs over nodes (words/variables)
• Both have ground-truth annotations (treebanks/bnlearn networks)
• Both use arc-level evaluation (UAS/LAS ↔ SHD/F1)

The biaffine pairwise scoring mechanism from Dozat & Manning (2017) was independently reinvented by AVICI and CauScale for causal structure learning — validating this connection.

Top Predictive Meta-Features

1. n_variables (30%) — network size (how many nodes in the graph)
2. max_pairwise_MI (24%) — strongest pairwise dependency (≈ biaffine arc score)
3. max_cramers_v (8%) — strongest association strength
4. max_entropy (7%) — variable complexity

Three Ideas Borrowed from Parsing

1. Biaffine-style pairwise features: MI and Cramér's V between all variable pairs = parsing's arc scores
2. Pairwise ranking (our best model): For each algorithm pair (A,B), predict which wins → count wins to rank. Inspired by pairwise tournament-style parser selection
3. Cross-___domain transfer: Train on well-characterized bnlearn networks → predict on new unseen datasets (= cross-lingual parser transfer)

🚀 Quick Start

from causal_selection.meta_learner.predictor import predict_best_algorithms
import pandas as pd

# Load your discrete dataset
df = pd.read_csv("my_discrete_data.csv")

# Get top-3 recommendations
result = predict_best_algorithms(df, k=3)
# Prints ranked algorithms with predicted accuracy and confidence

📁 Project Structure

causal_selection/
├── data/
│   ├── generator.py          # Load bnlearn networks, sample data, DAG→CPDAG
│   ├── bif_files/            # 14 bnlearn BIF files (asia through win95pts)
│   └── results/              # Benchmark CSVs: meta-features, SHD matrices
├── discovery/
│   ├── algorithms.py         # 9 algorithm adapters with timeout handling
│   └── evaluator.py          # SHD, F1, Precision, Recall computation
├── features/
│   └── extractor.py          # 34 meta-features across 5 tiers
├── meta_learner/
│   ├── trainer.py            # Multi-Output RF/GBM + LONO-CV evaluation
│   └── predictor.py          # Inference: dataset → top-3 prediction
├── models/
│   ├── meta_learner.pkl      # Trained GBM (multi-output fallback)
│   ├── pairwise_model.pkl    # Pairwise ranking GBM (best model)
│   └── scaler.pkl            # Feature scaler
├── benchmark.py              # Full benchmark orchestration
├── run_benchmark.py          # Resumable benchmark runner
└── augment_and_improve.py    # Data augmentation + model improvement

📈 Benchmark Data

• 14 bnlearn networks: asia, cancer, earthquake, sachs, survey, alarm, barley, child, insurance, mildew, water, hailfinder, hepar2, win95pts
• 178 dataset configs: 122 original + 56 augmented (variable subsampling, sample-size variation, noise injection)
• 1,600+ algorithm runs: 9 algorithms × 178 configs with per-algorithm timeout

Data Augmentation Strategies

• Variable subsampling: Drop 20-40% of variables to create virtual sub-networks
• Sample-size variation: Generate N=300, 750, 1500, 3000 for each network
• Noise injection: Randomly flip 5-10% of categorical values

🔧 Dependencies

causal-learn>=0.1.4
pgmpy>=0.1.25
scikit-learn>=1.8
pandas
numpy
scipy
joblib

📚 References

• Causal-Copilot (arxiv:2504.13263) — Closest existing algorithm selection system
• AVICI (arxiv:2205.12934) — Amortized causal structure learning (biaffine architecture)
• CauScale (arxiv:2602.08629) — Scalable neural causal discovery
• Dozat & Manning (arxiv:1611.01734) — Deep Biaffine Attention for dependency parsing
• TreeCRF (arxiv:2005.00975) — Global structural training loss for parsing
• SATzilla (arxiv:1401.2474) — Algorithm selection via meta-learning
• bnlearn (bnlearn.com) — Bayesian network benchmark repository

🔮 Future Work (Phase 2)

1. Biaffine neural encoder: Pre-train a neural feature extractor that learns variable-pair "arc scores"
2. Portfolio regret loss (TreeCRF-inspired): Global ranking optimization instead of per-algorithm MSE
3. Hyperparameter co-selection: Predict not just which algorithm but optimal hyperparameters (CASH)
4. Ensemble prediction: Run top-3 and vote on edges across their CPDAGs

License

MIT