A formula for assessing style is described and applied to compositions written by adult students of English as a second language. Style is defined as the total effect of what is done by a writer in the composing process, including choice of words, organization, and sentence and paragraph strategies. Earlier attempts to quantify style are reviewed. The formula proposed by Williams (1979) posits that the clearest style is that in which agents and subjects coincide. It is asserted that, in English, an agent and what it does semantically are manifested redundantly by at least three grammatical structures: the grammatically defined roles of subject and predicate, the sequence of subject-agent followed by what it does, and the form class of subject-agent as a noun and what it does as a verb. Williams' metric was applied to 10 compositions and the resulting ratings were compared with ratings obtained by other means. The results indicated that Williams' metric has concurrent validity for second language compositions. (RW)