The purpose of this study is to begin work toward a grammatical assessment measure that could bridge the gap between theoretical work on grammatical development, on the one hand, and tools such as the Michigan Test (which uses multiple-choice questions on vocabulary and grammar) or the American Council on the Teaching of Foreign Languages scale (which uses holistic descriptions of grammar use), on the other hand. Such a measure would need to be practical to administer with large groups. Two proposals of grammatical development (processability theory, Pienemann, 1998, 2005; and organic grammar, Vainikka & Young-Scholten, 2006) were applied to short samples of spontaneous production data from 48 adult second-language learners of English from mixed first-language backgrounds. The rapid profile scale successfully accounted for the learners’ development but is of somewhat limited use with short samples of data. The organic grammar placement scale may need to be further refined, but it includes important indicators of grammatical development. A preliminary proposal for using a combined measure with a rubric is presented.