Constant effects and the independence of variants in controlled judgment data

This article proposes that Kroch’s (1989) Constant Rate Hypothesis – the generalization that contextual effects tend to be stable in processes of diachronic variation in production data – be extended to synchronic variation in controlled judgment data. Two recent, large-sample judgment experiments are discussed suggesting that shared contextual effects across speakers in acceptability judgments can be used to infer a single abstract source for patterns of variation across superficially different contexts. At the same time, the results suggest that not all sets of variants – or “ways of saying the same thing” (Labov 1972: 271) – are linguistic variables of this formally defined type.