Project Blue Book Special Report (second copy)

This is Project Blue Book Special Report No. 14, "Analysis of Reports of Unidentified Aerial Objects," Project No. 10073, dated 5 May 1955. The study reduced about 4,000 sighting reports received by the U.S. Air Force between June 1947 and December 1952 to IBM punched cards and analyzed them statistically, including chi square tests comparing knowns with unknowns. It concludes that the reports very probably do not represent technological developments beyond present scientific knowledge, and it notes that no case produced physical evidence.

..mum.
Total Less Unknown
Per Cent
80 70 60- 50 40 30 20
Oi
oi
10
1 1
. r
1 1 1 I I 1 _^^l
•
One'
Two
Three
to
ten
Eleven
or
more
Not stated
Unknown
Per Cent
10 20 30 40 50 60 70 80
| 1 1 'I I I 1 1 1
FIGURE 19 COMPARISON OF KNOWN AND UNKNOWN. OBJECT SIGHTINGS BY NUMBER OF
OBJECTS PER SIGHTING, 1947-1952
A-7497