Demonstration / Decision systems
Eligibility Lab: explainable rules for multi-market products
An interactive multi-market eligibility policy simulator comparing Singapore, EU, and US decisions with versioned rules, reason codes, review paths, and next-best actions.
Multi-market policy simulator
One applicant. Three materially different decisions.
Change the applicant once and evaluate the same normalized facts against three versioned market policies. Select any result to inspect the rule trace and customer path.
Eligible
All required rules passed with no manual-review conditions.
The product problem
Eligibility begins as a handful of conditions and quickly becomes a product system: market availability, age, identity state, address evidence, product configuration, and policy versions all interact. The backend must return more than yes or no; product, mobile, support, risk, and QA need to understand the same decision.
The model
Normalize inputs once, evaluate explicit versioned rules, and return stable reason codes alongside the decision. Persist the inputs, rule version, outcome, and reasons as one audit event so the system can explain what it knew at decision time.
- Separate fact collection from policy evaluation.
- Make rule order and precedence explicit.
- Return reason codes that are safe for downstream product flows.
- Version policies so historical decisions remain reproducible.
How I would test it
Start with decision tables, then generate boundary cases around every threshold and market difference. Add invariants—for example, identical normalized inputs and rule versions must always produce identical results—and retain counterexamples as regression tests.
What this demonstrates
Product judgment belongs in the contract. A good eligibility API makes complex policy legible, gives support teams useful evidence, allows QA to reason about coverage, and lets the business evolve rules without turning every change into an incident.