Though we cannot compute the true bias for any real system, the computation is trivial for this baseline.
the true V-measure is equal to 0, as the baseline can be regarded as a limiting case of a stochastic system that picks up one of the m clusters under the uniform distribution with m → ∞; the mutual information between any class labels and clustering produced by such model equals 0 for every m. the ML estimate for the V-measure isV(k, c) = 2Ĥ(c)/(log N +Ĥ(c)).