where ΔΣ = Σ 1 -Σ 2 is the difference in description length and it is assumed that both model classes are equally likely a priori, meaning that 𝑃(ℋ 1 ) = 𝑃(ℋ 2 ). Thus, using Λ 1 is identical to using the MDL criterion, but allows for quantification of the degree of confidence with Λ 1 < 1, indicating a preference for ℋ 2 and partition {𝒃 𝑙 } ′ .