| # Quality Scoring |
|
|
| ## Design Philosophy |
|
|
| Quality scores are not just "how good is this entry" — they measure **trustworthiness |
| for machine learning**. An entry might be perfectly valid DFT data but score low |
| on novelty (too many similar entries). This is intentional: a diverse, well-sampled |
| dataset produces better models than one with 100,000 copies of Li₂O. |
|
|
| ## Score Components |
|
|
| The quality score is a composite of five sub-scores (max 95, normalized to 0-100): |
|
|
| | Sub-score | Max | What it measures | |
| |-----------|-----|-----------------| |
| | **Geometry** | 25 | Structure quality: nsites, volume, density reasonableness | |
| | **DFT** | 20 | Property completeness and physical range | |
| | **Metadata** | 15 | Space group, density, structure_json presence | |
| | **Novelty** | 20 | How unique this entry is relative to the dataset (diversity bonus) | |
| | **Chemical** | 15 | Chemical reasonableness (element combinations, valence, etc.) | |
| |
| ## Calibration |
| |
| We proved the quality score is monotonically related to label reliability: |
| |
| | Score Bin | N | Valid% | SG% | Complete% | FE Out% | FE MAE | |
| |-----------|---|--------|-----|-----------|---------|--------| |
| | 50-60 | 4,807 | 0.1% | 0.1% | 0.0% | 0.31% | — | |
| | 60-70 | 32,273 | 27.9% | 2.0% | 0.0% | 0.01% | 0.80 | |
| | 70-80 | 146,001 | 77.4% | 8.8% | 0.1% | 0.00% | 0.23 | |
| | 80-90 | 83,649 | 85.2% | 97.4% | 82.7% | 0.00% | 0.18 | |
| |
| **Key finding**: score 80-90 is research-grade: |
| - 97.4% have verified space groups |
| - 0% property outliers |
| - 0.18 eV/atom cross-source FE MAE (close to DFT noise floor) |
| |
| ## Thresholds |
| |
| | Threshold | Purpose | |
| |-----------|---------| |
| | ≥ 70 | Validated tier — basic research use | |
| | ≥ 80 | Strict Gold — publication-grade, benchmark-ready | |
| | ≥ 90 | Not yet achieved — reserved for experimentally validated entries | |
| |
| ## Score Distribution |
| |
| ``` |
| 50-60: 4,807 (1.8%) ██ |
| 60-70: 32,273 (12.1%) ████████████ |
| 70-80: 146,001 (54.7%) ████████████████████████████████████████████████ |
| 80-90: 83,649 (31.4%) ████████████████████████ |
| 90-100: 0 (0.0%) |
| ``` |
| |
| ## Sub-score Means |
| |
| | Sub-score | Mean | Max | |
| |-----------|------|-----| |
| | Geometry | 16.7 | 25 | |
| | DFT | 19.7 | 20 | |
| | Metadata | 11.8 | 15 | |
| | Novelty | 14.2 | 20 | |
| | Chemical | 15.0 | 15 | |
| |
| ## Limitations |
| |
| 1. No score ≥ 90 — scoring is conservative; no entry has "perfect" metadata |
| 2. OQMD entries score lower on metadata (missing space group until computed) |
| 3. Novelty scoring may unfairly penalize common structures |
| |
