---
license: other
license_name: cc-by-4-0-with-sf-attribution
license_link: LICENSE
language:
- en
library_name: lightgbm
tags:
- prediction-markets
- forecasting
- calibration
- brier
- tabular-classification
- gradient-boosting
- lightgbm
- xgboost
- catboost
- time-series
- kalshi
- polymarket
- simplefunctions
pipeline_tag: tabular-classification
model-index:
- name: sf-ml-baseline-v0.1
  results:
  - task:
      type: tabular-classification
      name: 24h direction forecast (V1 x T1)
    metrics:
    - type: brier
      value: 0.2294
      name: Brier score
    - type: brier_improvement
      value: 0.0206
      name: Improvement vs coinflip baseline (0.2500)
  - task:
      type: tabular-classification
      name: 24h resolution forecast (V2 x T4)
    metrics:
    - type: brier
      value: 0.1681
      name: Brier score (XGBoost)
    - type: brier_improvement
      value: 0.0086
      name: Improvement vs market-price/100 baseline (0.1767)
---

# sf-ml-baseline v0.1

**What it is**: gradient-boosted tree ensembles that predict prediction-market outcomes from engineered microstructure features.

**Published**: 2026-04-19 (initial, time-capsule — see "Retrain plan" below).
**Trained on**: 11 days of SimpleFunctions (`market_indicator_history` + `marketwide_resolutions`) — 2026-04-08 → 2026-04-19.
**License**: CC-BY-4.0 with SimpleFunctions attribution — see `LICENSE`.
**Author**: SimpleFunctions — https://simplefunctions.dev
**Model repo**: https://huggingface.co/SimpleFunctions/sf-ml-baseline *(pending upload)*

## Why release this

Nobody has published a calibrated feature-based baseline for prediction-market forecasting. All prior art (Halawi 2024, Schoenegger 2024, AIA 2025) uses LLM + news retrieval. We release this as the **feature-based reference** that LLM systems should ensemble with.

**Brier scores (vs market-implied baseline, 95% CI):**

| Task | Model | Brier | CI | Δ vs baseline |
|------|-------|------:|---|---:|
| V1 × T1: direction 24h | LGBM 3-seed | 0.2295 | [0.2290, 0.2299] | **−0.0205** (vs coinflip 0.2500) |
| V1 × T1: direction 24h | XGBoost 3-seed | 0.2296 | [0.2292, 0.2301] | −0.0204 |
| V1 × T1: direction 24h | CatBoost 3-seed | 0.2295 | [0.2290, 0.2299] | −0.0205 |
| **V1 × T1: direction 24h** | **Ensemble (3-model × 3-seed = 9)** | **0.2294** | [0.2289, 0.2299] | **−0.0206** |
| V2 × T4: resolution 24h | XGBoost 3-seed | 0.1681 | [0.1605, 0.1759] | −0.0086 (vs price/100 = 0.1767) |

Statistically significant (non-overlapping 95% CI) on V1 × T1 at 246,862 test samples.

## Install

```bash
pip install lightgbm xgboost catboost numpy pandas
```

## Use

```python
from pathlib import Path
from sf_ml_baseline import SFBaseline

model = SFBaseline(weights_dir='sf-ml-baseline/weights')

# Direction forecast: probability that the 24h-forward price will be HIGHER than now.
# Features: current price (cents, 0-100), 24h price delta (cents),
#           implicit yield (%), calibration ratio index (unitless), calibration variability ratio.
p_up = model.predict_direction(price_cents=55, delta_cents=3, iy=12.5, cri=0.6, cvr=0.8)
print(f'P(price rises in next 24h) = {p_up:.3f}')

# Or batch-predict from a DataFrame:
import pandas as pd
df = pd.DataFrame([
    {'price_cents': 55, 'delta_cents': 3, 'iy': 12.5, 'cri': 0.6, 'cvr': 0.8},
    {'price_cents': 82, 'delta_cents': -1, 'iy': 4.5, 'cri': 0.3, 'cvr': 0.9},
])
probas = model.predict_direction_batch(df)
```

See `predict.py` for the full inference code.

## Architecture

- **Features (V1)**: `price_cents`, `delta_cents` (24h price change), `iy` (implicit yield), `cri` (calibration ratio index), `cvr` (calibration variability ratio). Spec: SimpleFunctions [indicator documentation](https://simplefunctions.dev/concepts).
- **Models**: 3 LightGBM + 3 XGBoost + 3 CatBoost, each trained with different seeds. Ensemble predictions by simple mean.
- **Split**: temporal — 80% train / 24h embargo / 20% test. 90/10 inner train/val split for early stopping.
- **Target T1**: binary `sign(price(t+24h) - price(t))`, excludes no-move rows (delta==0 at t+24h).
- **Target T4**: `resolved_outcome` ∈ {0, 1} for markets that resolved in 22-26h after the feature capture time.

## Known limitations

1. **Only 11 days of training data.** The full feature history table (`market_indicator_history`) was introduced to SF's data pipeline on 2026-04-08. A proper 30d+ / 180d+ re-train is scheduled; see "Retrain plan" below.
2. **5 base features only.** `market_indicator_history` holds a compact subset of the full indicator stack. The live `market_indicators` table has ~20 features (`iyYes`, `iyNo`, `ee`, `las`, `vr`, `iar`, `rv`, `adjIy`, `cvrDelta`, `overround`, etc.) but only for the current snapshot. Future versions will store history for the full feature set.
3. **`cvr` has 0% feature importance in the direction model.** Investigate whether the window/computation needs tuning.
4. **V2 × T4 (rolling features + resolution label) is below the 0.01 Brier gate globally** — works well on Crypto (Δ=−0.041) and Commodities (Δ=−0.036) but not Sports (Δ=−0.006) or Financials (+0.004, model worse).
5. **Do not use for live trading without backtesting against your own execution model.** This is a calibration baseline, not a PnL strategy.

## Retrain plan

**v0.1 is a time-capsule.** Planned retrains:

| Version | Trigger | When | What changes |
|---------|---------|------|------|
| v0.2 | R2 dump archive ≥ 30d of indicator history | ~2026-05-20 | Same architecture, more data; per-category specialist models for Crypto/Commodities/Sports |
| v0.3 | Full indicator feature set stored in history (schema change) | TBD | V1 grows from 5 → 20 features; re-run Phase A.3 full grid |
| v1.0 | ≥ 6 months of R2 data | ~2026-10 | FT-Transformer + TabPFN + ensemble; formal paper submission (ICLR 2027 FinAI Workshop) |

## Reproduce

```bash
git clone https://github.com/spfunctions/simplefunctions-landing  # (private — OSS mirror pending)
cd simplefunctions-landing
source scripts/ml/.venv/bin/activate

# Data pull (uses DIRECT_DATABASE_URL in .env.local)
python scripts/ml/phase-a/01-pull-training-data.py

# Train
python scripts/ml/phase-a/02-train-lgbm.py
python scripts/ml/phase-a/04-bakeoff.py

# Evaluate
python scripts/ml/phase-a/03-evaluate.py
```

All hyperparameters are documented inline. 3-seed ensembling uses {42, 137, 2026}.

## Citation

```bibtex
@software{sf_ml_baseline_v0_1,
  author       = {SimpleFunctions},
  title        = {{sf-ml-baseline}: A feature-based prediction-market forecaster},
  year         = {2026},
  version      = {0.1},
  publisher    = {SimpleFunctions},
  url          = {https://simplefunctions.dev/opensource/sf-ml-baseline},
  license      = {CC-BY-4.0 with SimpleFunctions attribution}
}
```

## See also

- `docs/ml/phase-a-investigation.md` — 10 open-question investigation (SPEC-19 §13)
- `docs/ml/phase-a-results.md` — gate decision + per-category breakdown
- `.claude/specs/SPEC-19-model-deep-investigation.md` — full 6-phase research plan