Project Blue Book Special Report (second copy)

a significant number of fairly complete reports by reliable observers re-
mained unexplained. Although no evidence existed that unexplained reports
of sightings constituted a physical threat to the security of the U. S. , in
March, 1952, the Air Force decided that all reports of unidentified
aerial objects should be investigated and evaluated to determine if "flying
saucers" represented technological developments not known to this country.
Originally, the problem involved the preparation and analysis of about
1,300 reports accumulated by the Air Force between 1947 and the end of
March, 1952. During the course of the work, the number of reports sub-
mitted for analysis and evaluation more than tripled, the result of the un-
precedented increase in observations during 1952. Accordingly, this study
is based on a number of reports considered to be large enough for a p_re^-
lirrmm£y^statistical analysis, approximately 4, 000 reports.
This study was undertaken primarily to categorize the available
reports of sightings and to determine the probability that any of the reports
of unidentified aerial objects represented observations of "flying saucers".
With full cognizance of the quality of the data available for study, yet with
an awareness of the proportions this subject has assumed at times in the
public mind,, this work was undertaken with all the seriousness accorded
to a straightforward scientific investigation. In order to establish the
probability that any of the reports of unidentified aerial objects represented
observations of "flying saucers", it was necessary to make an attempt to
answer the question "What is a * flying saucer1 ? " . However, it must be
emphasized that this was only incidental to the primary purpose of the
study, the determination of the probability that any of the reports of un-
identified aerial objects represented observations of "flying saucers", as
defined on Page 1. ^
The basic technique for this study consisted of reducing the available
data to a form suitable for mechanical manipulation, a prerequisite for the
application of preliminary statistical methods. One of International
Business Machine Corporation' s systems was chosen as the best available
mechanical equipment.
The reduction of data contained in sighting reports into a form suit-
able for transfer to IBM punched cards was extremely difficult ""and time
consuming.
For this study a panel of consultants was formed, consisting of both
experts -within and outside ATIC. During the course of the work, guidance
and advice were received from the panel. The professional experience .
available from the panel covered major scientific fields arid numerous
specialized fields.
All records and working papers of this study have been carefully
preserved in an orderly fashion suitable for ready reference. These