For decades, Australian political watchers have leaned on one figure above all others. Not the primary vote share. Not preferred prime minister. The two-party-preferred number, the 2pp, the share each major bloc ends up with once preferences are distributed. It is two things at once: the headline number pollsters publish, and the figure the electoral commission reports on the night. In most elections it has been the number that decides who governs. That dual role is why pundits reach for it (with exceptions in the top left and bottom right quadrants of the next chart).
