This paper introduces an approach to teaching ethics as design in a new course entitled Design Ethics, team-taught by a philosopher and an engineer/designer. The course follows a problem-based learning model in which groups of students work through the phases of the design process on a project for a local client, considering the design values and the ethical values in play in each decision along the way. Their acquisition of ethical thinking skills and moral imagination are assessed with a novel approach, which uses Latent Semantic Analysis to computationally analyze their responses to short answer ethical design questions before and after the course. Students also completed an ethical thinking survey and self-efficacy assessment. Results show statistically significant differences for a number of metrics, and promise for further research into teaching ethics as design.