How much support does the record provide?
The Evidence Strength Scale (ESS) describes how strongly the available record supports a reported event as precisely described.
Working draft · terminology and criteria are under development.Read the complete draft (Markdown)
Evidence Strength Scale
ESS applies to the reported event as described, not to the person making a report and not to a proposed explanation. A strong record can support an event that ultimately has a familiar cause; the scale measures documentation, not strangeness.
- 0
Third-party or hearsay report
The reported event is relayed by someone who did not directly experience or observe it.
- 1
Single report
One person provides an account of an experience or observation.
- 2
Corroborated report
There is independent agreement or basic contemporaneous documentation.
- 3
Meaningfully documented event
Corroborating documentation is available, but important gaps in record provenance, completeness, or context remain.
- 4
Strongly documented event
Original records are preserved, record provenance and timing are documented, relevant context is available, and multiple sources substantially agree.
- 5
Independently verified under documented conditions
ESS 4 conditions are met, key variables are monitored, raw records are available, and the relevant record or process receives meaningful independent review.
ESS 5 does not require that an event can be produced on demand or transferred to a laboratory. It recognizes the strongest practical form of field documentation: an event captured under monitored conditions and independently verified.