Trust

Sources & methodology

Outbreak Signal aggregates public-health information from official agencies and reputable secondary reporting. Every claim on this site links back to a source, with the date we accessed it. We sort sources into three tiers.

How the tiers work

  • Tier 1 — Official

    WHO, CDC, ECDC, PAHO, national ministries of health, and other official public-health agencies. Tier 1 can stand alone as factual.

  • Tier 2 — Reputable

    Major news outlets, peer-reviewed journals, ProMED-style outbreak intelligence (when publicly accessible). Can support factual claims; we prefer Tier 1 corroboration.

  • Tier 3 — Unverified signal

    Social media, blogs, forums. Must be labeled “unverified signal” and cannot stand alone as a factual claim. Tier 3 is off by default in the radar and is surfaced only when the user explicitly toggles it on.

Source registry

The current source registry used by Outbreak Signal. Phase 1 is a small, manually maintained list. Phase 3 introduces scheduled fetchers under human review.

Tier 1

Tier 2

  • ReportedReuters Health

    Tier 2 reputable secondary reporting; corroborate with Tier 1 where possible.

  • ReportedAssociated Press — Health

    Tier 2 reputable secondary reporting.

  • ReportedProMED-mail

    Tier 2 outbreak intelligence (publicly accessible posts only). Prefer Tier 1 corroboration.

Tier 3

  • No Tier 3 sources currently in the registry.

Current source coverage

Source coverage

Tier mix in the registry

  • Tier 1 — Official

    WHO, CDC, ECDC, PAHO, ministries.

    4

  • Tier 2 — Reputable

    Major outlets, peer-reviewed journals, ProMED.

    3

  • Tier 3 — Unverified

    Social media, blogs, forums. Cannot stand alone as factual.

    off

Tier 1 sources can stand alone as factual. Tier 3 sources cannot. Tier 3 is off by default and surfaces only with an explicit toggle.