How does the suite score tenant affordability?

Question

Accepted Answer

The letting-agent suite ships a tenant-affordability heuristic on the response when the agent provides `affordability.annualRent` (and optionally `affordability.tenantStatedIncome`).

How it works:

1. Compute requiredAnnualIncome = annualRent × 3 (the classic UK 33% rent-to-income letting test).
2. Take effectiveIncome from one of: tenantStatedIncome (best signal when the agent has it); otherwise postcode-area median household income from the v1 LA-level lookup table (top ~50 UK LAs by population, ONS / HMRC sourced).
3. Score = clamp((effectiveIncome / requiredAnnualIncome) × 80, 0, 100).
4. Tier: comfortable (score ≥ 85) / adequate (≥ 70) / stretched (≥ 50) / unaffordable (< 50) / unknown (no income data + postcode outside the v1 lookup).

The response also returns:
  - rentRatio (annualRent / effectiveIncome)
  - effectiveIncome + incomeSource ('tenant-stated' or 'postcode-median')
  - laName (the LA the postcode resolved to)
  - notes (plain-English explanation of the heuristic + caveats)

What this is: a useful early flag for the agent at the AML stage. "Tenant claims £80k income to live in a £30k-median area" surfaces immediately as a green light; "rent is 60% of stated income" surfaces as red. It catches mismatches before referencing comes back.

What this is NOT: a substitute for tenant referencing. Goodlord / HomeLet / Vouch verify income against pay-stubs, employer references, and bank statements; we do not. The heuristic uses postcode median (which is a proxy) when no stated income is provided. Any decline-or-accept decision should run through proper referencing where the agent has access.

v1 limitations:
  - LA-level income lookup, not LSOA-level (top ~50 LAs covered; postcodes outside return 'unknown' rather than guessing).
  - Income figures rounded from ONS / HMRC household-income deciles 2023-2024; refreshed annually with each ONS bulletin.
  - The follow-up LSOA-level ingest is on the roadmap and replaces the table with much finer-grained per-postcode figures.

How does the suite score tenant affordability?

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