Evidence Leverage Ladder

Problem addressed

Teams either repeat supplier testing or accept vendor claims without connecting them to intended use.

Limitation of existing practice

Document inventories measure availability, not whether evidence addresses the customer’s risk.

Proposed method: inputs and steps

1. Classify the evidence from claim to observable control.
2. Confirm product, version, module, and environment relevance.
3. Assess execution credibility and unresolved defects.
4. Map coverage to the customer failure analysis.
5. Generate only the evidence needed for the residual gap.

Decision outputs

• Supplier-evidence map
• Leverage rationale
• Customer confirmation plan

Worked example

Core SaaS signature logic is leveraged from traceable vendor testing; customer tests concentrate on identity mapping, configured meanings, approval order, and exported-record linkage.

When to use—and when not to

Use when: Qualifying configurable products, SaaS services, platforms, and shared infrastructure.

Do not use as-is when: Evidence cannot be matched to the deployed service or contradicts observed behavior.

Limitations

Access depends on supplier transparency and contractual rights.

Inspection questions

• What exactly was leveraged?
• Why is it credible?
• What customer-specific gap remained?