The Vallee Classification System

The Vallee classification system (VCS) was developed by Dr. Jacques Vallee to classify UFO sightings. This system provides more details than other systems like the Hynek classification system, and therefore, used more by ufologists.

The classifications are as follows:

MA Rating: Describes the manoeuvres of a UFO

MA1: A UFO has been observed which travels in an erratic trajectory, i.e. vertical drop manoeuvres.

MA2: MA1 plus any physical effects caused by the UFO.

MA3: MA1 plus any entities observed on board.

MA4: Manoeuvres accompanied by a sense of reality transformation for the observer.

MA5: A manoeuvre that results in a permanent injury or death of a witness

FB Rating: The fly-by rating, describes the flight characteristics of the UFO

FB1: A sighting of a UFO travelling in a straight line across the sky.

FB2: FB1 plus physical evidence

FB3: A fly-by where entities are observed on board.

FB4: A fly-by where the witness experienced a transformation of reality into the object or its occupants.

FB5: A fly-by that results in a permanent injury or death of a witness.

CE Rating: Close encounter rating, describes the level of contact between the witness and UFO

CE1: UFO comes within 500 feet of the witness, but no after effects are experienced by the witness or the surrounding area.

CE2: A CE1 that leaves landing traces or injuries to the witness.

CE3: Entities have been observed on the UFO

CE4: The witness has been abducted

CE5: CE4 that results in permanent psychological injuries or death.

SVP Rating: describes the credibility of the witness's account of the UFO sighting

A rating out of four is given for the three categories of the source: reliability, site visit and possible explanation.
For example:

Reliability: 1, site visit: 2 and possible explanation: 3 =123 (A rating of 222 or higher indicates the case was reported by a reliable source.)

Source Reliability Rating:

0: Unknown or unreliable source.
1: Report attributed to a known source of unknown or un-calibrated reliability.
2: Reliable source, second-hand.
3: Reliable source, firsthand.
4: Firsthand personal interview with the witness by a source of proven reliability.

Site Visit Rating:

0: No site visit, or answer unknown
1: Site visited by a casual person not familiar with the phenomena.
2: Site visited by persons familiar with the phenomena.
3: Site visited by a reliable investigator with some experience.
4: Site visited by a skilled analyst

Possible Explanations Rating:

0: Data consistent with one or more natural causes.
1: Natural explanation requires only slight modification of the data.
2: Natural explanation requires major alteration of one parameter.
3: Natural explanation requires major alterations of several parameters
4: No natural explanation possible, given the evidence.