The identification of known objects was routine, and caused no excitement. The excitement and serious interest occurred when we received UFO reports in which the observer was reliable and the stimuli could not be identified.... Of the several thousand UFO reports that the Air Force has received since 1947 [through ~1957], some 15 to 20 percent fall into this category called unknown. This means that the observer was not affected by any determinable psychological quirks and that after exhaustive investigation the object that was reported could not be identified. To be classed as an unknown, a UFO report also had to be "good," meaning that it had to come from a competent observer and had to contain a reasonable amount of data.... [Any report lacking sufficient data, like the stereotypical distant-light-in-the-sky report], if it was received by Project Blue Book, was stamped "Insufficient Data for Evaluation" and dropped into the dead file, where it became a mere statistic."

USAF Captain Edward J. Ruppelt's "Report on Unidentified Flying Objects", pp.9-10

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"Much more disturbing are the indications from my limited review of BB cases that there may be as many as possibly 4,000 Unexplained UFO cases miscategorized as IFO's in the BB files. McDonald similarly stated in 1968 at his CASI lecture that from his review of BB cases he estimated that 30-40% of 12,000 cases were Unexplained, or about 3,600 to 4,800. These are mostly military cases and many involve radar".

Comprehensive Catalog of 1,600 Project BLUE BOOK UFO Unknowns

The Craig papers also reveal that despite publicly reporting over 30 % “unknowns” in the final report (and astonishingly reporting that there was nothing of scientific worth to the UFO subject) the reality was that more than 50% were “unknown.”

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Originally posted by karl 12
Article dealing with Blue Book Special Report 14, the 4602d Air Intelligence Service Squadron and the mystery of extra 1000 unexplained UFO incident reports which went missing along the way:

It is also worthy of noting that Air Force Blue Book recorded 2,344 sightings in the 1947 through 1952 time period. Special Report Number 14 said that the Air Force recorded 3,201 reports. This is nearly one thousand more reports than listed by Blue Book. Where did the extra reports come from? Many suspect that these reports were collected by the 4602 AISS and that only reports which had more mundane explanations ever reached Blue Book.

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Almost from the beginning of the Air Force UFO investigations, patterns were starting to emerge, and the cover-up was already in place. Researcher & NCP member, Jan Aldrich notes:

In a 1952 LOOK article, Ruppelt mentions a file of 63 cases of UFOs over nuclear installations, but such a file is not in currently declassified Blue Book files.

NCP-16: National Security, Missing Files, The Nuclear Key

Contrary to the Alr Force claim, thousands of UFO reports have been--and still are--withheld. Of these, 244- released in 1949 are no longer available.

NICAP UFO Investigator (pdf file)

BBSR14

This report consisted of a detailed analysis of UFO reports received by the Air Force from 1947 through 1952. The press release of the report contained a brief synopsis of reports received in early 1955. This was a good report, but the Air Force deliberately tried to mislead the public. The report actually showed that 21.5% of the sightings were unknowns. However, the first page of the report contains the press release which stated that only 3% percent of the sightings were unknowns. (This only represented reports received in early 1955 and not reports in the actual study which covered 1947-1952.) The Air Force also tried to weight the report by removing astronomical phenomena from the study. This had an effect of showing that known and unknown sightings were more similar (using characteristics such as color, speed, number of objects, aerial maneuvers etc.) However, dropping astronomical phenomena didn't much difference in the outcome of the report, but it illustrates how the Air Force was trying to deceive the public. In other words the Air Force didn't appear to want the public to know the results of there own study of UFOs.

Condon report:

University of Colorado to conduct a study of UFOs. Dr. Edward Condon was head of the group who conducted the study at the university. Many of the cases reported to Project Blue Book were examined. The conclusion of the report was that UFOs were not worthy of further scientific study. Most of the report was "filler" consisting of topics like how radar echoes are affected by weather anomalies, psychological implications, optics, plasmas, etc. Little space was allocated to specific UFO cases and all of the "unexplained cases" were put in the middle of the report. Dr. Condon also wrote his conclusions at the head of the report. Most scientific papers have the conclusions at the end of report.

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REFERENCES:

Title: Unusual Incidents
To: Director of Intelligence, General Staff, U.S. Army
Authors: C. P. Cabell, Major General, USAF, Director of Intelligence, Office of Deputy Chief of Staff, Operations.
Date: February 23, 1949
Length: 1 page.
Classification: CONFIDENTIAL

Reports that detailed investigations of all UFO incidents reported from June 1946 to date have been conducted and only 20% have been explained. "There is no tangible evidence which would support a theory that any incidents are attributable to activity of a foreign nation. The Air Materiel Command of the USAF is continuing investigations of each unexplained event."

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"I have found there are real objects under in intelligent control being seen on the ground and in our skies worldwide. The unknowns have varied over the decades from 22 percent in my own civilian files, 30 percent in the University of Colorda Condon Committee scientific studies, to at least 40 percent (recently revised) found in the U.S. Air Force Project Blue Book military investigations. This is not acceptable, no matter who is doing the investigations"

George Fawcett, UFO researcher (Ronald Story, Encyclopedia)

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Captain Ruppelt discusses radar UFO tracking and 25% unexplained rate.

60 reports in 2 weeks:

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"UFOs: A Case Study in Public Mis-information"

After covering the history of UFOs from 1947 onward, McDonald speaks about one of the cases that he felt literally dragged him into the whole controversy; Portage County, Ravenna Ohio, April 17th, 1966

McDonald: This case of April 17th, 1966 is a beautiful illustration of how the percentage of unidentified shall be reduced to a minimum..

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