Interesting. Thanks Paul. The study however, states at the onset that it doesn't take into account migrants following a constant bearing in the open ocean. We know Polynesians followed a constant bearing from 'Voyages of Discovery' by Ben Finney. The alpha star of the Fishook constellation was kept directly above the mast.
It is also concerned with drift voyages which we know from Webb and Levisons computer simulated drift studies wasn't how the Pacific was settled. It was purposive and as Kirch points out, must have been motivated by an 'ingrained ethic of adbventure and discovery',