Top-20 Methodology
To generalize from Top-10 to Top-20, we maintain structural bucketing and add rank robustness plus psychoacoustic interpretability.
Composite ranking
\(S = w_1 S_{structure} + w_2 S_{coverage} + w_3 S_{chord\_balance} + w_4 S_{emotion\_range}\)
Uncertainty
\(CI_{95\%}(S)=\bar S \pm 1.96\,\sigma_{bootstrap}\)