The conventional wisdom regarding the diachronic process whereby phonetic phenomena become phonologized appears to be the ‘error accumulation’ model, so called by Baker, Archangeli, and Mielke (2011). Under this model, biases in the phonetic context result in production or perception errors, which are misapprehended by listeners as target productions, and over time accumulate into new target productions. In this article, I explore the predictions of the hypocorrection model for one phonetic change (prevoiceless /ay/-raising) in detail. I argue that properties of the phonetic context underpredict and mischaracterize the contextual conditioning on this phonetic change. Rather, it appears that categorical, phonological conditioning is present from the very onset of this change.