What Do Interval Cycles Have To Do With Tonal Harmony?

Woolhouse's (2010) central empirical finding is a relatively high correlation between his interval-cycle proximity (ICP) model and the theorist Walter Piston's (1979) Table of Usual Root Progressions. The fit between these two models can be understood in terms of a classification of chord progressions by root interval class (second, third, fifth) and directionality (strong, weak). The ICP model does not perform as well on data on chord progressions in Tymoczko's (forthcoming) corpora of music by Bach and Mozart. The alternative MHP model (Quinn, 2010) does not fit the Piston data as well as the ICP model, but it fits the corpus data better than the ICP model.