Figure 6

Initiative impacts and relative entropy over different years. In the upper panels, we show estimates of the initiative impact \(\lambda _{A}\) and \(\lambda _{B}\) as defined in Eqs. (10) and (11). We see that the polarization effects for self-identified Democrats are larger than for self-identified Republicans. We also compute the relative entropy usning Eq. (14) and show the results in the lower panels. \(P_{\text{Year}}\), \(P^{\prime }_{1994}\) and \(P^{\prime }_{\lambda }\) are the distributions of the data in different years, of the model in 1994 and of our model in different years, respectively. Blue disks represent Democrats and red disks represent Republicans