Identification studies of UFOs

Identifying unidentified flying objects is a difficult task due to the normally poor quality of the evidence provided by those who report sighting the objects. Nevertheless, most officially investigated UFO sightings, such as from the U.S. Air Force's Project Blue Book, have been identified as being due to honest misidentifications of natural phenomena, aircraft, or other prosaic explanations. In early U.S. Air Force attempts to explain UFO sightings, unexplained sightings routinely numbered over one in five reports. However, in early 1953, right after the CIA's Robertson Panel, percentages of unexplained sightings dropped precipitously, usually being only a few percent in any given year. When Project Blue Book closed down in 1970, only 6% of all cases were classified as being truly unidentified.

UFOs that can be explained are sometimes termed "IFOs" or Identified Flying Objects.

The following are some major studies undertaken during the past 50 years that reported on identification of UFOs:

In contrast, much more conservative numbers for the percentage of UFOs were arrived at individually by astronomer Allan Hendry, who was the chief investigator for the Center for UFO Studies (CUFOS). CUFOS was founded by astronomer Dr. Allen Hynek (who had been a consultant for the Air Force’s Project Blue Book) to provide a serious scientific investigation into UFOs. Hendry spent 15 months personally investigating 1,307 UFO reports. In 1979, Hendry published his conclusions in The UFO Handbook: A Guide to Investigating, Evaluating, and Reporting UFO Sightings. Hendry admitted that he would like to find evidence for extraterrestrials but noted that the vast majority of cases had prosaic explanations. He found 89% of reports definitely or probably identifiable and only 9% unidentified. “Hardcore” cases—well-documented events which defied any conceivable conventional explanation—made up only 1.5% of the reports.

Project Blue Book Special Report No. 14 was compiled between 1951 and 1954, and included 3201 reported UFO sightings. Battelle employed four scientific analysts, who sought to divide cases into "knowns", "unknowns", and a third category of "insufficient information." They also broke down knowns and unknowns into four categories of quality, from excellent to poor. In order for a case to be deemed "identified", two analysts had to independently agree on a solution and for a case to be called "unidentified", all four analysts had to agree. A report classified as "unidentified" was defined as: "Those reports of sightings wherein the description of the object and its maneuvers could not be fitted to the pattern of any known object or phenomenon."

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