* impl/research

Survey of academic literature on class imbalance in deep learning, relevant to ROLL's thesis positioning.

** Key Papers

| Paper | Venue | Node |
|-------|-------|------|
| CLIMB (arXiv:2505.17451) | NeurIPS 2025 | — |
| [[id:8f59b736-04ea-4d11-9195-30d125a127f8][impl/paper-beyond-rebalancing]] | 2024 | detailed node |
| Simplifying NN Training Under Class Imbalance (arXiv:2312.02517) | 2023 | — |
| Investigating Group DRO (arXiv:2303.02505) | 2023 | — |
| [[id:bf0fc08a-e806-48df-b188-7a2c4c41c693][impl/paper-tabpfn]] | ICLR 2023 | detailed node |
| Survey on Imbalanced Learning (Springer 2024) | Springer AI Review | — |
| Rethinking Class Imbalance (arXiv:2305.03900) | 2023 | — |

** Competing Strategies

Methods the literature benchmarks against (relevant as ROLL baselines):

- *Resampling*: SMOTE, ADASYN, CSMOUTE, BorderlineSMOTE, ROSE
- *Cost-sensitive*: class weighting, focal loss, asymmetric loss
- *Ensemble*: BalancedBagging, EasyEnsemble, RUSBoost, BalancedRandomForest
- *Threshold moving*: post-hoc calibration on decision threshold
- *DL-specific*: LDAM-DRW, M2m, MiSLAS, BBN (mostly image long-tail)
- *Tabular DL baselines*: XGBoost, LightGBM, CatBoost, MLP, ResNet, FT-Transformer, [[id:bf0fc08a-e806-48df-b188-7a2c4c41c693][impl/paper-tabpfn]]
- *CLIMB finding*: ensembles dominate; naive rebalancing (SMOTE alone) often underperforms

Metrics used: AUC-ROC, G-Mean, F1, Precision/Recall. AUC and G-Mean are the standard for imbalanced eval.
ROLL's TPR-at-FPR framing is non-standard but more practically useful — position this as an advantage.

** Dataset Coverage vs Literature

*** Well Covered by ROLL
- All glass variants (glass0–6) — standard KEEL
- Yeast3, ecoli-0-1_vs_5, wisconsin, cleveland, pima, haberman, iris0, vowel0, vehicle2, page-blocks, new-thyroid1, led7digit
- Adult, Forest Cover, Bank Marketing (medium tabular)
- Credit Card Fraud (~285K, IR 577:1) — common in fraud literature

*** Gaps vs Literature (datasets in papers ROLL doesn't have)

| Dataset | IR | Samples | Appears In |
|---------|----|---------|------------|
| Abalone9-18 | ~130 | 731 | [[id:8f59b736-04ea-4d11-9195-30d125a127f8][Beyond Rebalancing]], CLIMB |
| Annthyroid | 7.2 | 6916 | [[id:8f59b736-04ea-4d11-9195-30d125a127f8][Beyond Rebalancing]], many UCI surveys |
| Satellite | 22 | 6435 | [[id:8f59b736-04ea-4d11-9195-30d125a127f8][Beyond Rebalancing]] |
| Segment | 6 | 2310 | [[id:8f59b736-04ea-4d11-9195-30d125a127f8][Beyond Rebalancing]] |
| Yeast4/5/6 | 8–33 | ~1484 | [[id:8f59b736-04ea-4d11-9195-30d125a127f8][Beyond Rebalancing]], CLIMB |
| Ecoli4 | 15.8 | 336 | [[id:8f59b736-04ea-4d11-9195-30d125a127f8][Beyond Rebalancing]] |
| KC1/KC2/PC1/CM1 (software) | 5–13 | 415–1783 | [[id:8f59b736-04ea-4d11-9195-30d125a127f8][Beyond Rebalancing]] |
| Pen-local/Pen-global | 9–671 | 7291 | [[id:8f59b736-04ea-4d11-9195-30d125a127f8][Beyond Rebalancing]] |

*** Non-Standard or Unusual in ROLL
- *Higgs*: ROLL samples 500K balanced (50/50) — not a standard imbalanced benchmark; physics ML context
- *Home Credit*: Kaggle competition dataset; rare in academic imbalance papers
- *CIFAR-10 binary* (class 1 vs rest, IR ~9): DL imbalance papers use long-tail formulation instead — results not directly comparable to LDAM/MiSLAS tables

** Recommendations for Baseline Strengthening

Priority additions (available in KEEL, low effort):
1. Yeast4, Yeast5, Yeast6 — stress-test high IR range
2. Annthyroid — one of the most cited UCI imbalanced datasets
3. Abalone9-18 — extreme IR (130:1), covers the hard regime
4. Ecoli4 — rounds out ecoli coverage at IR 15.8

Lower priority (useful if sweeping many baselines):
5. Satellite, Segment, Pen-local — common in full KEEL sweeps
6. KC1/PC1 — software metrics datasets; different domain from biology/finance

** Paper Subnodes

- [[id:bf0fc08a-e806-48df-b188-7a2c4c41c693][impl/paper-tabpfn]] — TabPFN: in-context learning for small tabular classification (ICLR 2023)
- [[id:8f59b736-04ea-4d11-9195-30d125a127f8][impl/paper-beyond-rebalancing]] — benchmark of 12 classifiers under imbalance, no rebalancing (2024)