The Synthetic Data Lifecycle: From Seeds to Evidence
By Gwylym Owen — 18–24 min read
Executive Summary
AethergenPlatform supports schema design, generation, validation, and evidence packaging—enabling delivery without PHI/PII, with artifacts buyers can evaluate and adopt as of September 2025.
Lifecycle Stages
The process:
- Schema: Define entities, relations, vocabularies, and constraints—set the stage!
- Seeds: Minimal/redacted aggregates to learn structure—plant the seeds!
- Generation: Craft realistic corpora with parameterised scenarios—create the illusion!
- Validation: Fidelity/utility metrics with CIs—validate results.
- Privacy: Probes and optional DP budgets—keep it secret, keep it safe!
- Packaging: Parquet/Delta, notebooks, and samples—wrap it up!
- Evidence: Signed bundle with metrics/configs/seeds/hashes—seal the deal!
Design Patterns
Practical patterns:
- Copulas/conditional generators for joint structure—connect the dots!
- Sequence models for episodes and temporal effects—tell the tale!
- Scenario overlays for rare events and stress tests—add some flair!
KPIs
Metrics to monitor:
- Fidelity to marginals and joints—keep it real!
- Utility against baseline detectors—prove the power!
- Privacy probe advantage vs random—lock it tight!
- Analyst yield at operating budgets—maximize the yield!
Evidence Integration
Operational integration:
- CI builds evidence; hashes recorded; dashboards exported—automated process.
- Bundle attached to change-control and procurement files—tie it up!
- Refresh cadence declared (e.g., monthly)—keep it fresh!
Case Study
Scenario: An insurer’s staged rollout.
An insurer could use the lifecycle to ship a claims corpus plus detectors. Evidence might show stability across regions and include a rollback SOP. Procurement could sign off within a simulated two‑week cycle as of September 2025.
FAQ
Can we skip seeds?
Seeds (or aggregates) anchor realism. If starting with public priors, we can tighten later as policy allows.
What about rare classes?
Scenario overlays and targeted augmentations help preserve tails; limits are disclosed in evidence.
Can we export dashboards?
Yes—HTML/PDF artifacts are bundled for offline review.
How do we handle regulator audits?
We deliver reproducible artifacts and documented limits; sensitive data stays on your infrastructure.
Can we attach private annexes for regulators?
Yes—annexes can ship with independent manifests; public bundles link without exposing sensitive content.
Glossary
- Evidence Bundle: Signed metrics/configs/hashes for reproducibility.
- Operating Point: Threshold aligned to business costs.
- DP: Differential privacy—your privacy shield!
- PSI: Population Stability Index for drift—your drift detector!
- CI: Confidence interval around estimates.
Checklist
Cast it right:
- Schema and vocabularies versioned—lock the blueprint!
- Generation recipes and parameters logged—track provenance.
- Validation and privacy probes pass thresholds—test the charm!
- Packaging and evidence verified—finalize artifacts.
Contact Sales →
Recipe Manifest
recipe:
schema: schemas/claims_v3.yaml
generator: copula+sequence
scenarios:
- upcoding: {prevalence: 0.03, factor: 1.2}
- duplicate_billing: {delay_days: 7}
outputs: parquet
Validation Dashboard Contents
Peek inside the crystal ball:
- Marginals and joint comparisons (key fields)—see the fit!
- Temporal effects (seasonality, inter-arrival)—feel the rhythm!
- Utility baselines at candidate thresholds—measure performance.
Privacy Probes
Guard the secrets:
- Membership inference advantage vs random—test the cloak!
- Attribute disclosure on sensitive fields—check the shield!
- Optional DP budget and composition notes—add the lock!
CI Example
steps:
- generate_small
- validate
- run_probes
- evidence_bundle
artifacts: [parquet, metrics.json, plots.html, manifest.json]
Evidence Manifest
{
"version": "2025.01",
"artifacts": ["metrics.json", "plots.html", "sbom.json"],
"hashes": {"metrics.json": "..."}
}
Runbook
Checklist:
- Change detected → regenerate evidence—cast anew!
- Compare against gates; if fail, fix or revert.
- Attach bundle to change-control; notify stakeholders.
Risks & Mitigations
Defend the realm:
- Tail under-coverage → targeted augmentations; disclose limits—fill the gaps!
- Overfitting to synthetic quirks → ablation checks; sanity tests—keep it real!
- Schema drift → versioning and automated diffs—stay on track!
Procurement Checklist
Seal the deal:
- Evidence meets thresholds with CIs—prove the power!
- Privacy probes under limits—guard the secrets!
- SBOM and hashes verified—check the ingredients!
- Refresh cadence and rollback defined—keep it flowing!
Schema Designer
Craft the foundation:
- Entity definitions with visibility labels and constraints—build the structure!
- Vocabulary management with versions and diffs—evolve the lexicon!
- Referential integrity checks and range constraints—keep it solid!
Seeds Policy
Guard the roots:
- Minimal seeds; access controls; retention timelines—protect the source!
- Provenance logs and review cadence—track the origin!
Generation Deep Dive
Unleash the creativity:
- Copulas for joint distributions; sequence models for timelines—weave the fabric!
- Graph generators for networks (AML/fraud)—connect the web!
- Scenario overlays with prevalence/severity controls—add the twists!
Validation Details
Test the potion:
- Marginals, joints, temporal checks with tolerances—check the fit!
- Baseline detectors at OP; effect sizes with CIs—measure the boost!
- Drift early-warning indicators—spot the shifts!
Privacy Details
Security:
- Membership and attribute probes with thresholds and CIs—test the defense!
- Optional DP budgets with expected impact notes—balance the power!
Packaging Details
Packaging:
- Parquet/Delta outputs; notebooks and sample slices—handy tools!
- Unity Catalog registration; comments linking evidence IDs—easy access!
Evidence Details
Seal the scroll:
- Signed metrics, configs, seeds, and hashes—locked tight!
- HTML/PDF dashboards; SBOM; manifest—full disclosure!
- Change-control references and deprecation notes—keep it current!
Case Studies
More examples:
- Payments AML: Graph overlay with mule rings; OP gains +15% with stability bands ≤0.02—simulated win!
- Industrial Vision: Lighting profiles; fallback models; golden sets approved in a week—simulated success!
Templates
acceptance:
bundle_id: string
op: string
stability: string
privacy: string
latency: string
decision: APPROVE|REJECT
Detailed Schema Catalog
entities:
Patient: {id: string, age: int, region: enum[NA,EU,APAC]}
Provider: {id: string, specialty: enum, region: enum}
Facility: {id: string, type: enum, region: enum}
Claim: {id: string, patient_id: ref Patient.id, provider_id: ref Provider.id,
facility_id: ref Facility.id, date: date, pos: enum, amount: decimal}
LineItem: {id: string, claim_id: ref Claim.id, cpt: string, icd10: string, units: int}
relations:
Patient 1..* Claim
Claim 1..* LineItem
constraints:
Claim.amount >= 0
LineItem.units > 0
vocabularies:
CPT_v12: {...}
ICD10_subset: {...}
Reference Constraints
Keep it grounded:
- Foreign keys enforced in packaging QA (referential integrity)—no loose ends!
- Domain ranges (age ∈ [0, 120], units ∈ [1, 99])—set the boundaries!
- Semantic checks (CPT family compatibility with specialty)—make sense!
Entity–Relationship Examples
Patient(id) ──< Claim(id) ──< LineItem(id)
│ │ \
└── region └── provider_id ──> Provider(id)
\
└─ facility_id ──> Facility(id)
Seeds Governance Checklist
Protect the source:
- Minimise fields; aggregate whenever feasible—keep it lean!
- Access logged and reviewed; time-bound permissions—secure it!
- Retention policy documented; periodic purge windows—clean slate!
Generation Parameter Tables
param, default, min, max, note
amount.ln_mu, 4.1, 3.8, 4.6, log-normal mean
amount.ln_sigma, 0.7, 0.5, 0.9, tail width
interarrival.lambda1, 0.3, 0.1, 0.6, short gap component
interarrival.lambda2, 0.8, 0.4, 1.2, long gap component
mix.weight, 0.4, 0.2, 0.6, mixture proportion
Overlay Library
overlays:
upcoding: {prevalence: 0.03, factor: 1.2}
unbundling: {prevalence: 0.01}
phantom_provider: {distance_km: >150, time_collision: true}
duplicate_billing: {delay_days: 7}
doctor_shopping: {window_days: 14, device_reuse: 0.25}
Overlay Composition Rules
Blend with care:
- Prevent impossible co-occurrences (e.g., mutually exclusive scenarios)—no clashes!
- Cap total prevalence to preserve realism—keep it believable!
- Log overlay seeds and parameters in manifest—track provenance.
Validation Worksheets
field, ks_pvalue, pass
amount, 0.21, yes
units, 0.34, yes
pos, 0.08, borderline (flag)
Operating Point Selection
Given budget alerts/day = B and volume/day = V, choose threshold θ s.t.
FPR(θ) ≈ B / V. Validate precision/recall at θ with CIs.
Effect Size Computation
base = evaluate(cfg_base)
for factor in factors:
cfg = tweak(cfg_base, factor)
result = evaluate(cfg)
delta = result.kpi_op - base.kpi_op
ci = bootstrap_ci(result - base)
record(factor, delta, ci)
Drift Monitors
monitors:
input_psi:
fields: [amount, pos]
threshold: 0.2
outcome_delta:
by_segment: [region, product]
threshold: 0.05
Privacy Methodology
Guard the vault:
- Training an attacker classifier to distinguish real vs synthetic; report AUC−0.5—test the disguise!
- Attribute disclosure via predictive models compared to baselines—check the leaks!
- Optional DP with composition accounting; disclose ε, δ and expected utility change.
Packaging Artifacts Catalog
Deliver the goods:
- Data (Parquet/Delta) with Unity Catalog registration—ready to use!
- Notebooks (trial, OP evaluation)—hands-on tools!
- Docs (README, schema, limits)—clear guides!
- Evidence bundle (metrics, plots, configs, sbom, manifest)—full proof!
Evidence Manifests
{
"version": "2025.01",
"artifacts": ["metrics/utility@op.json", "plots/stability_bars.html"],
"hashes": {"metrics/utility@op.json": "sha256:..."},
"env": {"python": "3.11", "numpy": "1.26.4"}
}
Unity Catalog Comments
COMMENT ON TABLE prod.ai.claims IS 'Purpose: fraud triage; OP: fpr=1%; Evidence: manifest 2025.01.';
Buyer Notebook
# 1) Load sample table
# 2) Run UDF at OP threshold
# 3) Compute OP metrics with CIs
# 4) Review stability summary
Audit File Tree
release_2025_01/
├─ metrics/
├─ plots/
├─ configs/
├─ privacy/
├─ sbom.json
├─ manifest.json
└─ README.html
Risk Register
risk, likelihood, impact, control, owner
tail_undercoverage, med, med, overlays+limits, data_lead
probe_regression, low, high, gates+waiver_policy, privacy_lead
SLA Mapping
Operational expectations:
- Evidence regeneration: next business day; bundle ID increments—quick fixes!
- Incident triage: same day for production promotions—fast response!
- Dashboard export fixes: 24h—smooth updates!
Closing
Schema, seeds, generation, overlays, validation, privacy, packaging, evidence—each stage forms a repeatable process. AethergenPlatform ensures the trail is auditable, so you can progress from pilot to production with confidence.