Grounded in the principle that writing assessment should be locally developed and controlled, this article describes a study that contextualizes and validates the decisions that students make in the modified Directed Self-Placement (DSP) process used at the University of Michigan. The authors present results of a detailed text analysis of students' DSP essays, showing key differences between the writing of students who self-selected into a mainstream first-year writing course and that of students who self selected into a preparatory course. Using both rhetorical move analysis and corpus-based text analysis, the examination provides information that can, in addition to validating student decisions, equip students with a rhetorically reflexive awareness of genre and offer an alternative to externally imposed writing assessment. (Contains 5 tables and 11 notes.)