We apply the Admiralty scale (also known as the NATO system) where feasible to express both source reliability and information credibility in a consistent, analyst-friendly format.
Credibility of information (1–6)
1 – Confirmed
2 – Probably true
3 – Possibly true
4 – Doubtfully true
5 – Improbable
6 – Cannot be judged
Reliability of source (A–F)
A – Completely reliable
B – Usually reliable
C – Fairly reliable
D – Not usually reliable
E – Unreliable
F – Cannot be judged
Admiralty rating format
We record ratings as a combined code (e.g., B2, C3), where the letter reflects source reliability and the number reflects information credibility.
| Source reliability \ Information credibility | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|
| A (Completely reliable) | A1 | A2 | A3 | A4 | A5 | A6 |
| B (Usually reliable) | B1 | B2 | B3 | B4 | B5 | B6 |
| C (Fairly reliable) | C1 | C2 | C3 | C4 | C5 | C6 |
| D (Not usually reliable) | D1 | D2 | D3 | D4 | D5 | D6 |
| E (Unreliable) | E1 | E2 | E3 | E4 | E5 | E6 |
| F (Cannot be judged) | F1 | F2 | F3 | F4 | F5 | F6 |
Definitions
Reliability of source
- A: Completely reliable – demonstrable history of complete accuracy.
- B: Usually reliable – generally accurate, with occasional errors.
- C: Fairly reliable – mixed record; as often right as wrong.
- D: Not usually reliable – more often inaccurate than accurate.
- E: Unreliable – known to provide inaccurate information.
- F: Cannot be judged – insufficient history or context to assess reliability.
Credibility of information
- 1: Confirmed – corroborated by independent, reliable sources.
- 2: Probably true – not fully confirmed, but assessed as likely accurate.
- 3: Possibly true – unconfirmed; plausibility is balanced.
- 4: Doubtfully true – unconfirmed and assessed as likely inaccurate.
- 5: Improbable – assessed as unlikely given available context or prior accuracy.
- 6: Cannot be judged – insufficient evidence to assess truth.
Further reading: