Note that responsiveness may be related to potential as follows: the closer the attitude metric is to its ceiling value, the more difficult it will be to register further increases through marketing. That phenomenon is readily incorporated in (3) by expressing the dependent variable as an odds ratio (e.g. Johansson 1979):
Y’t = Yt / (MAX-Yt) = c Y’t-1γ X1tβ1 X2 t β2 X3t β3 eut