Project Blue Book Special Report No. 14 was their massive statistical analysis of Blue Book cases to date, some 3200 by the time the report was completed in 1954. Even today, it represents the largest such study ever undertaken. Battelle employed four scientific analysts, who sought to divide cases into "knowns", "unknowns", and a third category of "insufficient information."
They also broke down knowns and unknowns into four categories of quality, from excellent to poor. E.g., cases deemed excellent might typically involve experienced witnesses such as airline pilots or trained military personnel, multiple witnesses, corroborating evidence such as radar contact or photographs, etc. In order for a case to be deemed a "known", only two analysts had to independently agree on a solution. However, for a case to be called an "unknown", all four analysts had to agree. Thus the criterion for an "unknown" was quite stringent.
The main results of the statistical analysis were:
- About 69% of the cases were judged known or identified (38% were considered conclusively identified while 31% were still "doubtfully" explained); about 9% fell into insufficient information. About 22% were deemed "unknown", down from the earlier 28% value of the Air Force studies.
- In the known category, 86% of the knowns were aircraft, balloons, or had astronomical explanations. Only 1.5% of all cases were judged to be psychological or "crackpot" cases. A "miscellaneous" category comprised 8% of all cases and included possible hoaxes.
- The higher the quality of the case, the more likely it was to be classified unknown. 35% of the excellent cases were deemed unknowns, as opposed to only 18% of the poorest cases.