Caelum Incognitum — The interactive encyclopedia of ufology
Strangeness and probability ratings
Classifications & scales
A rating system proposed by Allen Hynek: “strangeness” measures how far an account departs from the ordinary; “probability” assesses the reliability of the testimony (number and quality of witnesses, consistency, circumstances). A case that scores both very strange and very probable would be the most interesting for research. The two scores help set aside weak accounts.