evidence

Evidence — Claim Strength by Source Tier

Every claim carries the strength of its weakest source. State the tier; never let a weak source wear a strong claim.

Process

1. Tag the source tier for each fact before you use it:
   • Primary — original data, measurements, reproducible experiments.
   • Peer-reviewed — vetted by the field.
   • Secondary — reputable review/synthesis, one step from primary.
   • Anecdotal / single-source — one opinion, one vendor, one unverified report.
2. Match claim strength to tier. A secondary source supports "X is associated with Y", not "X causes Y".
3. Separate the proven from the likely from the unknown. Three buckets, no blurring.

Anti-Rationalization

• "It's probably true" → name the tier. "Probably" without a tier is a guess wearing a lab coat.
• "Multiple blogs said it" → multiple anecdotes are still anecdotal.
• "The vendor's whitepaper" → a vendor source serves the vendor; tier it down.

Evidence

• A claim is well-grounded when its highest-cited source tier matches the claim's asserted strength, and weaker tiers are labeled as such.

Red Flags

• Causal language ("causes", "proves") resting on correlational or single-source evidence.
• Treating a reputable name as proof (argument from authority).
• One source, stated as settled consensus.