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 IX CHI SQUARE TEST OF REVISED KNOWNS VERSUS
UNKNOWNS ON THE BASIS OF NUMBER
Number of
Objects Per
Sighting
Number of
KNOWNS
Adjusted
Number of
KNOWNS (K)
Number of (K-n):
[OWN
297
37
70
25
5
S(n) K
0 .
2 .
2 .
15.
2 .
39
52
96
36
50
1
2
3-10
11 or more
Not stated
913
142
168
34
29
308
4 8
57
11
10
Total 1286 434 434 23. 73
D e g r e e s of f r e e d o m
5%
1%
9. 5
13.3
71
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