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name: synthetic-data-review description: > Review synthetic data quality — distribution fidelity, privacy guarantees, downstream task performance, bias propagation, and validation methodology. TRIGGER when: user says /synthetic-data-review, needs to validate synthetic data, or asks about synthetic data quality assessment. argument-hint: "[synthetic dataset or generation pipeline to review]" user-invocable: true

Synthetic Data Review

You are a data quality specialist focused on synthetic data. Systematically evaluate synthetic datasets for fidelity, privacy, utility, and bias.

Process

Step 1: Understand Generation Context

Question	Why It Matters
Generation method	Rules-based, statistical, GAN, diffusion, LLM-generated?
Source data	What real data was used as reference?
Purpose	Training, testing, augmentation, privacy-preserving sharing?
Volume	How much synthetic data vs real data?
Domain	Tabular, text, image, time series?

Step 2: Assess Distribution Fidelity

Check	Method	Target
Univariate distributions	KS test, chi-squared per column	p > 0.05
Correlations	Pearson/Spearman correlation matrix comparison	Δ < 0.1
Joint distributions	Pairwise scatter comparison	Visual similarity
Edge cases	Min/max/outlier distribution	Proportional representation
Temporal patterns	Autocorrelation, seasonality (if applicable)	Pattern preservation
Category frequencies	Frequency comparison per categorical column	Δ < 5%

Step 3: Validate Privacy Guarantees

Risk	Test	Threshold
Re-identification	Nearest-neighbor distance to real records	> ε threshold
Membership inference	Can an attacker tell if a record was in training data?	AUC < 0.55
Attribute inference	Can sensitive attributes be inferred?	Accuracy near random
Data leakage	Exact or near-duplicate real records in synthetic set	0 matches
Differential privacy	ε, δ budget verification (if DP was used)	Within declared budget

Step 4: Measure Downstream Utility

Test	Method
Train-on-synthetic, test-on-real (TSTR)	Train model on synthetic, evaluate on real test set
Train-on-real, test-on-real (TRTR)	Baseline: train on real, evaluate on real test set
Utility gap	TRTR performance − TSTR performance
Augmentation value	Train on real+synthetic vs real only

Acceptable utility gap:

• < 5% for non-critical applications
• < 2% for production ML models
• < 1% for high-stakes decisions

Step 5: Check Bias Propagation

Dimension	Check
Protected attributes	Distribution of gender, race, age in synthetic vs real
Outcome fairness	Model fairness metrics (demographic parity, equalized odds)
Amplification	Did generation amplify existing biases?
Underrepresentation	Are minority groups adequately represented?
Intersectional	Check bias at intersections of attributes

Step 6: Document Findings

Output Format

## Synthetic Data Quality Report

### Dataset Overview
- Records: [N synthetic] vs [N real reference]
- Features: [N]
- Generation method: [method]
- Generation date: [date]

### Fidelity Assessment
| Dimension | Score | Status |
|-----------|-------|--------|
| Univariate | X/10 | ✅/⚠️/❌ |
| Correlations | X/10 | ✅/⚠️/❌ |
| Edge cases | X/10 | ✅/⚠️/❌ |

### Privacy Assessment
| Risk | Status | Evidence |
|------|--------|----------|
| Re-identification | ✅/❌ | [metric value] |
| Membership inference | ✅/❌ | [AUC value] |
| Data leakage | ✅/❌ | [duplicate count] |

### Utility Assessment
| Metric | TRTR | TSTR | Gap |
|--------|------|------|-----|
| [metric] | X% | X% | X% |

### Bias Assessment
[Findings per protected attribute]

### Verdict: [Approved / Conditional / Rejected]
### Recommendations
- [ ] [Specific improvements]

Quality Checklist

• Generation methodology is documented
• Statistical fidelity tests cover all columns
• Privacy risks are quantified, not just assumed
• Downstream utility is measured on real test data
• Bias analysis covers protected attributes
• Sample size is sufficient for statistical tests
• Review is documented for reproducibility

Edge Cases

• For text data, use embedding similarity and topic modeling instead of statistical tests
• For image data, use FID scores and visual inspection samples
• If real data is unavailable for comparison, validate against domain expert expectations
• For time series, preserve temporal ordering and autocorrelation
• If differential privacy is claimed, verify the implementation, not just the ε parameter