A classification methodology consolidated over decades  

Since 2008, a more detailed classification (A/B/C/D1/D2) has been used by the GEIPAN. It is based on 2 main criteria: the weirdness and the consistency. 

This methodology involves:

  1. The identification of research hypotheses that could explain the full weirdness of the sighting (as perceived by the witness) and the evaluation of their probability. Each hypothesis is based on one or several physical (such as stars or plasma) or psychological (such as perception effects, false memories) known phenomena;
  2. The characterisation of the sighting weirdness (E, ranging from 0 to 1). It is the distance to what is “known”, measured by the difference: 1 minus the probability of the strongest hypothesis. If the weirdness is above 0.5, the GEIPAN has no explanation (no hypothesis seems appropriate).
  3. The characterisation of the consistency of the sighting depending of the amount of gathered information (number of witnesses, number and precision of the responses, presence or not of photographic materials…) and its reliability (coherence, reliability of the witnesses, existing links between the different witnesses…). 

Finally, it requires to apply the following basic and common-sense principle: the more the weirdness is strong (i.e. the less the best hypothesis is probable), the more the consistency must be strong:

  • to validate the “unexplained” when the weirdness is above 0.5. D1 (strange) or D2 (very strange) cases
  • to validate the explanation when the weirdness is below 0.5. A (almost proved hypothesis) or B (probable explanation) cases.
  • otherwise, the sighting is declared “ not workable” due to lack of reliable data: C cases.

For D1 and D2 cases, on-site investigations, including a meeting with the witness and a cognitive interview, are systematically performed. Very often, the final classification is defined following the opinion of the group of experts. However, an eventual reclassification is always possible when a new element come in. The D cases need periodical re-evaluation

Statistics of the GEIPAN

Across the last 40 years, 9 724 testimonies (representing around 5 300 cases) were analysed by the GEIPAN. Around 10% of the cases led to on-site investigations.

63,2 % of A and B cases are explained by some misidentification or by some perception mistake.

33,4 % of the sightings cannot be assess.

Around 3,4% of the sightings remain unexplained.

Over the last decade, the rate of unexplained cases dropped to 2%. Today, the GEIPAN has sped up the reappraisal of old D cases with 50 of them re-investigated and explained in 2017.

Globally, the GEIPAN is handling 1000 requests per year: more than half are treated by an immediate feedback to the witness or by directing the witness towards others entities. Around 200 lead to investigations with diffusion on the GEIPAN website (www.geipan.fr) of sighting reports and investigation conclusions, maintaining anonymity of witnesses.

What to think about unexplained cases ? Why so many ? 

Incompetency of the investigator ?

  • Challenges encountered by the investigator are multiple: difficulty in defining or ranking the different hypotheses, no or low competency sharing between investigators, not involving the right expert. Most of the time, the most important challenge is to gather from the witness the key element that will explain the particular previously resisting to analysis. A lack of empathy, an insufficient ability to listen, a closed question or a question asked at the wrong moment, can definitively stop the opportunity to find an explanation;

Lack of investigation resources ?

  • The GEIPAN resources are of course limited. An investigation can take up to 250 hours, but this remains rare. Old cases did not benefit from the now available powerful web-based and digital  tools; 

Hoaxes ?

  • Very rare (< 1%) and we know how to detect them (but we do not disclose how).

Pathological liars ? 

  • We can also detect them. Expert psychologists are then involved and work using the questionnaire or audio recordings. 

Hallucinations ? 

  • Sometimes it is obvious but in others cases, it can be difficult to detect. Hallucinations are not always pathological ones and can come from a witness whose behaviour and sayings rise no issue   apart from  the weirdness present in his/her sighting,. In this case, opinion of our expert psychologists will be decisive. They are then working from audio recordings made during the cognitive interview (authorized by the witnesses) or on-site by meeting the witnesses themselves. 

Unknown natural phenomena ?  

  • We can hope that explanations will come from the future. Some phenomena have already been explained by the Science’s progress: ball lightning, autokinetic phenomenon. For sure, others will also find an explanation. Moreover, progress is also coming from the acquired experience: some of the explained cases (for witch objective proofs are available) allowed to identify and characterize what brought weirdness in these sightings. Such cases are nowadays much easier to identify and help to explain some recent or old cases that remain unexplained. For example, laser spotlight reflections in the sky, group of birds in flight formation, perception mistakes…).  

 Flying aircrafts from an unknown origin? 

  • Of course, this hypothesis cannot be excluded, although in 40 years of investigations of the GEIPAN, no proofs have been found.

And what about the alien hypothesis? 

A large part of you, readers, is probably expecting some words on this matter. Having clearly said that the GEIPAN, to this day, has no proof of their existence, we will not formulate an opinion. An absence of proof does not make a proof of absence ! 

The alien hypothesis is constantly present in the work of the GEIPAN. It can be suggested or clearly expressed by the witness but also can only be present in his/her emotion in reaction to the sighting. Medias and journalists in particular have most of the time this aspect in mind during interviews, looking to find the best teaser or the best title for their paper. The GEIPAN’s work is also scrutinized and criticized by  some UFO blogs and associations who are pros of the alien hypothesis..

Not very far from the alien hypothesis stands the conspiracy theory which is also continuously present in the GEIPAN work: “the GEIPAN has been set up by the government to hide the truth”, “receives orders from the military”, etc…


All these theses must be managed by the GEIPAN in his daily work and clearly, GEIPAN respects all opinions and the need to believe.

Indeed, the fundamental question that may  bring some weirdness in the sky at any time is of high nobleness : what place man has when facing the immensity of the universe?

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