EMSR-b
Revenue management methods
Protection levels (Littlewood's rule, EMSR-b)
How many rooms to protect for a higher fare.
y₁ = F₁⁻¹(1 − p₂/p₁): protect as many rooms for the higher rate as keeps the probability of selling them no lower than the rate ratio
Calculate in the calculator →How to read the metric
The basis of nested booking limits; EMSR-b extends it to several rate classes.
Worked example
p₁ = 15 000, p₂ = 9 000, demand at p₁ ~ N(30, 10²) → y₁ = 30 + 10·z(0.4) ≈ 27 rooms.