In the maritime danger model, which expression represents the danger index?

• A. IS / (IS + (LLB + LLA + LUF))
• B. IS * (LLB + LLA + LUF) / LUF
• C. (IS + LLB) / (LLA + LUF)
• D. (LLB + LLA + LUF) / IS

Answer: (A)

In this maritime danger model, the danger index represents how dominant the danger signal is relative to all other risk factors by normalizing the danger signal against the total hazard. The expression IS / (IS + (LLB + LLA + LUF)) does exactly that: the numerator picks out the danger contribution, and the denominator adds together all contributions, producing a dimensionless value between 0 and 1. This means the index rises as IS grows, and falls when the other factors are large, reflecting the share of the overall hazard that comes from the danger signal. If IS is zero, the index is zero; if the other factors are zero, the index reaches one, showing the danger signal dominates.

Other forms wouldn’t provide the same intuitive, bounded measure. A product form can skew the scale and potentially exceed one, while using a different denominator could distort the proportional share of danger versus other factors. The chosen ratio cleanly captures the relative contribution of IS to the total hazard.