How many levels do the likelihood and consequence scales carry, respectively?

Answer

five likelihood levels and six consequence levels

Options - A. five likelihood levels and six consequence levels - B. five likelihood levels and five consequence levels - C. six likelihood levels and five consequence levels - D. four likelihood levels and six consequence levels Why - A. Correct — rare/unlikely/possible/likely/almost certain against insignificant/minor/moderate/major/catastrophic/doomsday. - B. The symmetric answer, and the commonest wrong one. The extra consequence level is Doomsday. - C. The asymmetry is real but this reverses it — likelihood is the shorter scale. - D. Likelihood has five, not four. The sixth consequence level, Doomsday, exists so that an organisation-ending outcome has a name of its own and cannot be averaged into Catastrophic.

Stallings & Brown 5e ch14 §14.4; ISO/IEC 27005