Text equivalent
Observation
What you can directly see or measure.
Hypothesis
A possible explanation to investigate.
Evidence
A record that tests the explanation.
Decision
A documented action by the responsible person.
Example: staining near a fastener is an observation. Corrosion is one possible explanation; appearance alone does not verify it.
Download diagram (SVG)Original educational diagram · Hardwood Failures · September 14, 2026.