Word Maturity: A New Metric for Word Knowledge

A new metric, Word Maturity, estimates the development by individual students of knowledge of every word in a large corpus. The metric is constructed by Latent Semantic Analysis modeling of word knowledge as a function of the reading that a simulated learner has done and is calibrated by its developing closeness in information content to that of a simulated literate adult. Individual human learner knowledge is aligned with the simulation by adaptive testing. Evidence of accuracy, example applications to vocabulary assessment, teaching and reading research, properties of the metric, and a conjecture about its possible wider importance are described.