Define the transition
Identify the organisation, system, approved baseline, proposed release, intended release date, assessor and decision owner. Fix the scope before judging the change.
Method and technical details
Five stages. Ten trigger domains. One reasoned route.
DELTA keeps the commercial proposition simple and the decision logic inspectable.
The assessment object
DELTA assesses a transition, not a product name.
BaselineApproved version V1
→ChangeDefined change event C
→ReleaseProposed version V2
The system name may remain unchanged while the model, data, interface, actor roles or operating environment change materially. DELTA therefore attaches its conclusion to the recorded versions and release conditions.
The DELTA method
Each letter performs a separate function.
Trigger domains
Ten factual domains drive the analysis.
Purpose and use
What the system does in practice, not only what the documentation calls it.
Affected people
New users, populations, geographies, languages or vulnerability contexts.
Decision consequence
Changes in ranking, selection, eligibility, pricing, enforcement or other significant effects.
Model and architecture
Model, provider, fine-tuning, retrieval, memory, routing, prompts and integrations.
Data and inference
New sources, categories, derived attributes, scores, profiles or feedback loops.
Autonomy and tools
Ability to initiate, sequence, decide, communicate or act through external systems.
Human oversight
Actual authority, information, time, competence and ability to intervene or reverse.
Actors and access
Provider, deployer, supplier, processor, recipient, authorised-user and onward-access changes.
Controls and incidents
Security, safety, access, resilience, monitoring, complaints, audits and unresolved failures.
Evidence readiness
Documentation, assessments, validation, notices, incident plans, rollback and approval.
Outcome hierarchy
The strictest triggered route governs.
- Deployment hold
A credible unresolved red-line, missing authority or unvalidated action capability blocks release.
- Full reassessment
A foundational assumption no longer holds, such as a material change in intended purpose or combined model and architecture.
- Targeted reassessment
Defined modules require review while unaffected evidence remains usable.
- Documentation update
The substantive basis remains intact, but records or notices need correction.
- Record only
The change remains within the documented envelope and no further route is triggered.
The user may adopt a stricter outcome. DELTA must never force a weaker route than the evidence supports.
Reassessment map
The output names the work, not merely the risk.
Triggered facts map to defined governance modules. The current pilot includes AI classification, intended purpose, value-chain responsibility, risk management, technical documentation, data protection, fundamental rights, human oversight, transparency and redress, testing and validation, security, vendor assurance, monitoring, consumer fairness, jurisdiction and tool permissions.
DELTA identifies which modules require attention. It does not pretend to complete every specialist exercise inside the same form.
Technical architecture
Local-first, deterministic and portable.
Application
Self-contained HTML, CSS and JavaScript that runs in a modern browser.
Processing
Assessment logic runs on the user’s device. The current package contains no server-side assessment engine.
Decision logic
Deterministic rules, visible triggers and a fixed outcome hierarchy. No generative model controls the result.
Local save
Optional browser localStorage save. Browser profiles, clearing settings and device access affect persistence and confidentiality.
Portability
JSON export and import preserve the structured record for later review or organisational storage.
Reporting
A concise first-page outcome followed by the full reasoning record. Browser print creates the PDF.
Versioning
Every report records the methodology version, rule-pack version and assessment date.
Dependencies
No external library, account or generative-AI service is required for the core prototype.
Progressive explanation
Short questions first. Detail when the user needs it.
The assessment uses compact fields and “Yes / No / Not sure” controls for trigger questions. Each complex question can expose a concise explanation without crowding the form. Clicking outside the explanation closes it.
This design follows one practical rule: an impatient non-specialist should understand the main question, while a specialist should still be able to inspect the boundary between answers.
Legal overlays
Facts travel. Legal conclusions need a current rule pack.
DELTA separates a jurisdiction-neutral factual comparison from versioned legal and governance overlays. The EU pilot rule pack uses the AI Act’s lifecycle concepts, including substantial modification and renewed conformity assessment for certain high-risk systems, while recognising that data protection, consumer law, employment law, equality law, sector rules and organisational approvals may create separate triggers.
The European Commission’s current materials confirm that substantial modification can require a fresh conformity assessment for a high-risk system, subject to the treatment of predetermined changes. DELTA does not reduce every change to that single legal threshold.
Inspect the implementation