Documents / FOIA release
This CIA-released copy of Project Blue Book Special Report No. 14 is dated 5 May 1955 and comes from the Air Technical Intelligence Center at Wright-Patterson Air Force Base. It is a statistical analysis of about 4,000 unidentified aerial object reports from 1947 through 1952, coded onto IBM punched cards with the help of a panel of scientists. The report concludes that such objects were highly unlikely to be technological developments beyond present-day scientific knowledge. It also found no valid evidence of physical matter.
“Jet Propulsion Laboratory”1 page
Read from the scan by GLM-OCR; expect the odd misread word.
Another interesting aspect of these new tests is that there are only two large discrepancies in all of the groups. These are for the 11 or more groups in the classification by number of objects per sighting and for the over-400-mph and meteor-like group for the classification by speed. The first was relatively unchanged by deletion of the astronomical sightings principally because of the concentration of sightings in the single-object category. The second was slightly increased by the removal of the astronomical sightings from the meteor-like classification. However, the main discrepancy, that of the excess of UNKNOWNS in the over-400-mph class, was little changed.
The results of these tests are inconclusive since they neither confirm nor deny that the UNKNOWNS are primarily unidentified KNOWNS, although they do indicate that relatively few of the UNKNOWNS are actually astronomical phenomena.
It was decided that this process would not be carried to its logical conclusion (that is, the determination of a linear combination of KNOWNS that would give a negligible chi square when compared with the UNKNOWNS), since it was felt that the inaccuracies in the reports would give a distorted and meaningless result.
## The "Flying Saucer" Model
The importance of the problem dictated a second approach, should the statistical results prove inconclusive. It was decided that an attempt would be made to describe the physical appearance, flight characteristics, and other attributes (that is, construct a model) of a class or classes of "flying saucers".
Preparatory to this attempt, a re-evaluation of the UNKNOWNS was necessary. This re-evaluation was accomplished by a panel composed only of persons previously associated with the work. Using all the UNKNOWNS reports available at ATIC, the panel made a careful study of the reports for the UNKNOWN SIGHTINGS in angle-of-sun-elevation Groups 1, 2, 3, 6, and 7 - those groups for which the sun was either above the horizon or less than $ 1 0^{\circ} $ in elevation below the horizon.
This study had two purposes. The first was to determine, with additional information such as the angle of elevation of the sun, how many of the UNKNOWNS might be ascribed to known phenomena. The second was to obtain those UNKNOWNS which were described in sufficient detail that they might be used to construct a model or models of "flying saucers".
It was decided to put any of the UNKNOWNS which might be known phenomena into a "possible KNOWN" category to denote the slightly lower confidence level which could be ascribed to these new evaluations. The FOIA release, from the cia-readingroom collection. The PDF is mirrored here; the original link is above. The text was read from the page images by GLM-OCR; expect the odd misread word. 312 pages are in the text index: search them above, or from the library's search.