Blue Book Special Report No. 14
The largest statistical study of UFO reports the United States government ever commissioned: the Battelle Memorial Institute's analysis of thousands of cases from 1947 to 1952.
In the wake of the 1952 sighting wave, the Air Force contracted the Battelle Memorial Institute to apply statistical methods to its accumulated UFO files. The analysts coded thousands of reports by shape, duration, colour, and observer type, and assessed each for whether it could be explained.
Released to the public in 1955, Special Report No. 14 found that a substantial fraction of the best-documented cases, those with the most reliable observers and the most complete data, remained unidentified, and that the better the report, the more likely it was to be unexplained. The full report, including its fold-out statistical tables, is below.
Source: US Air Force / Battelle Memorial Institute, declassified. Public domain (US Government work).
