differential_concentration
0.0 to 1.0, or null when the declared semantics are not categorical or are violatedDifferential concentration (field alias: phi_hat)
s = top 5 named masses (descending) + one residual bucket (explicit other + all lower-ranked mass); concentration = 1 − H(s) / ln(6), H(s) = −Σ s_i ln s_i
How concentrated the ranked hypothesis distribution is. Structural only: it does not measure correctness, calibration, evidence quality, or clinical reliability. The normalizer is fixed, so appending negligible hypotheses cannot inflate it.