Classification of UFO Sightings

Hynek Classification System
Type Code Description
Nocturnal Light NL UFO (lights) sighted at night time
Daylight Discs DD UFO (shapes) sighted at day time
Radar   UFO detected on radar
Radar-Visual RV UFO detected on radar with visual  mutual confirmation
Close Encounter of the First Kind CE1 UFO sighted at close range with no interaction with environment
Close Encounter of the Second Kind CE2 UFO sighted at close range with physical effect on animate and inanimate material
Close Encounter of the Third Kind CE3 UFO sighted at close range with occupants in or around it
Vallee Classification System
Type Code Description
Anomaly 1 AN1 Anomaly with no lasting physical effects (e.g. amorphous lights, explosions)
Anomaly 2 AN2 Anomaly with lasting physical effects (e.g. poltergeist phenomena, materialised objects, flattened grass)
Anomaly 3 AN3 Anomalies associated with entities (e.g. ghosts, yetis, elves, spirits)
Anomaly 4 AN4 Anomalies where witness experiences personal interaction with entities in entity's reality (e.g. near-death experiences, religious miracles and visions, out-of-body experiences)
Anomaly 5 AN5 Anomalous injuries or deaths (e.g. spontaneous combustion, inexplicable wounds, permanent healing)
Manoeuvre 1 MA1 UFO sighting involving object with discontinuous trajectory (e.g. a drop, manoeuvre or loop)
Manoeuvre 2 MA2 UFO sighting involving object with discontinuous trajectory plus physical effects (e.g. object triggering photocell for entire city)
Manoeuvre 3 MA3 UFO sighting involving object with discontinuous trajectory with occupants aboard
Manoeuvre 4 MA4 UFO manoeuvre where witness experiences transformation in his/her sense of reality
Manoeuvre 5 MA5 UFO manoeuvre where witness suffers permanent injury (or healing) or death
Fly-By 1 FB1 Simple UFO fly-by in the sky
Fly-By 2 FB2 Fly-by plus physical evidence
Fly-By 3 FB3 Fly-by with occupants aboard
Fly-By 4 FB4 Fly-by and witness experiences transformation of own reality into reality of the object or its occupants
Fly-By 5 FB5 Fly-by and witness experiences permanent injury
The SVP Credibility Rating*
First Digit: Source Reliability (S)
0 Unknown source or unreliable source
1 Report attributed to a known source of uncalibrated reliability
2 Reliable source, secondhand
3 Reliable source, firsthand
4 First hand personal interview with the witness by a source of proven reliability
Second Digit: Site Visit (V)
0 No site visit, or answer unknown
1 Site visit by a casual person not familiar with such phenomena
Site visit by persons familiar with such phenomena
3 Site visit by a reliable investigator with some experience
4 Site visit by a skilled analyst
Third Digit: Possible Explanations (P)
0 Data consistent with one or more natural causes
Natural explanation requires only slight modification of the data
2 Natural explanation requires gross alteration of one parameter
3 Natural explanation requires gross alteration of several parameter
No natural explanation possible, given the evidence
Other Classifications
Type Code Description
Close Encounters of the Fourth Kind CE4 UFO sighted together with occupants and witness is abducted
Close Encounters of the Fifth Kind CE5 Witness experiences personal contact with UFO entities (i.e. 'contactees')
Close Encounters of the Sixth Kind CE6 Death of human or animal resulting from encounter with UFO entity
Close Encounters of the Seventh Kind CE7 Interbreeding between human and alien


* Vallee uses a three-digit code to measure each UFO case. Each digit is taken from one of the SVP categories listed.


Hynek, J. A. The UFO Experience: A Scientific Inquiry. London: Corgi Books, 1974.

Joyce, J. The Weiser Field Guide to the Paranormal. San Francisco: Red Wheel/Weiser, LLC, 2011.

Vallee, J. Confrontations: A Scientist's Search for Alien Contact. New York: Ballantine Books, 1990.



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