GEIPAN’s classification methodology was rebuilt in 2008. It replaced the earlier subjective assessment approach with a quantitative and qualitative evaluation based on two specific parameters: étrangeté (strangeness) and consistance (consistency). Every UAP case is scored on both axes before a classification is assigned.
The Two Parameters
- Étrangeté (Strangeness, E): The measure of residual strangeness after the case has been compared against all known phenomena hypotheses. How strange is the observation, once everything that could explain it has been eliminated?
- Consistance (Consistency, C): The product of the quantity and reliability of data collected and submitted during the investigation. How solid is the evidence base? Objective data is weighted according to GEIPAN’s internal scale.
The Four Classifications
- A — Perfectly identified: The phenomenon has been unambiguously explained after investigation.
- B — Probably identified: GEIPAN’s hypothesis is considered very probable. The explanation is not certain but is the most defensible conclusion from the available evidence.
- C — Unidentified (insufficient data): The observation cannot be analysed because there is not enough information. This is a data quality verdict, not an anomaly verdict. The report may describe something genuinely unusual, but GEIPAN cannot evaluate it.
- D — Unexplained after investigation: GEIPAN conducted a full investigation and could not identify a known explanation. Divided into:
• D1: Strange but medium consistency — typically single witness, no photo or video.
• D2: Very strange and strong consistency — multiple independent witnesses AND/OR photographic or video evidence AND/OR physical ground traces. The highest evidential standard in the system.
How Classification Can Change
GEIPAN’s classification is not final. Cases C and D can be revisited at any time if new information becomes available. A case classified D1 can be upgraded to D2 if additional witnesses come forward or physical evidence is later documented. A case classified C can move to A if the witness provides the missing data point that enables identification. The system is designed to be living documentation, not a static verdict.
The D2 category — multiple witnesses, physical evidence, ground traces, still unexplained — is the hardest evidential standard any government UAP programme has ever defined for a genuinely anomalous case. GEIPAN’s published D2 count is currently zero in the dynamic statistics. When that number changes, it will matter.
Source: cnes-geipan.fr/fr/node/58787 (Classification page). cnes-geipan.fr/fr/node/58788 (Methodology). Rebuilt 2008.