Project Blue Book Special Report No. 14: Analysis of Reports of Unidentified Aerial Objects

Special Report No. 14 was issued by the U.S. Air Force's Air Technical Intelligence Center on 5 May 1955. It is a statistical study of about 4,000 reports of unidentified aerial objects from June 1947 to December 1952. The reports were reduced to IBM punched cards and analyzed with methods including chi square tests. The report concludes that the reports it examined are very unlikely to represent technology beyond present scientific knowledge, and it notes that no case produced valid physical evidence.

TABLE XII
Speed
Stationary
Less than 100 mph
100 to 400 mph
Over 400 mph
Meteor-like
Not stated
CHI SQUARE TJ
UNKNOWNS ON
Number of
KNOWNS
196
128
156
291
2 4
491
£ST OF REVISE
THE BASIS OF
Adjusted
Number of
KNOWNS (K)
66
43
53
98
8
166
D KNOWNS VERt
SPEED
Number of
UNKNOWNS (n)
53
26
58
145 1
16}
136
5US
X 2
( K - n ) 2
K
2. 56
6.72
0.47
~> Q C A
do. 54
5.42
f
Total 1286 434 434 43.71
Degrees of freedom
5%
1%
9.5
13.3
74