In studying language change, variationists are, naturally perhaps, more interested in the new, innovative form than in the old conservative one, and because of the actuation problem, investigations of changes in progress very rarely are able to shed light on the change in its very earliest stages. In this article, I suggest that we should perhaps pay more attention than we have at present to the origins of the change (in addition to its route and destination) and the nature of the conservative form if we are to chart ongoing changes in an accurate way. Here, I highlight an example of a feature of New Zealand English (NZE) (realizations of the mouth diphthong with front mid-open onsets) that has, until recently, been assumed to have resulted from a change of the Southern Shift-kind—a raising and fronting to [εʊ~εƏ]—but which, as I demonstrate using contemporary and past dialectological, as well as sociodemographic evidence, did not undergo this change in this way. Indeed, the supposedly conservative [aʊ] form has barely been used at all as a conversational vernacular variant in NZE. I argue here that the present-day NZE realization is far more likely to be the outcome of a process of dialect leveling operating on the mixture of forms brought to New Zealand by British and Irish migrants in the 19th century. The moral of the story is that if we think we observe a change in progress from A to B, we need to provide evidence not just of the existence of B, but also of the prior existence of A.