We gratefully acknowledge Dr. Matthew Steele for help in generating web diagrams and Dr. Ross Nehm for extensive comments and revisions of early drafts of this article. We also thank the Automated Analysis of Constructed Response collaboration for helpful conversations while preparing the manuscript. Additionally, we thank collaborating instructors for collecting data and for the feedback that helped inform our rubric revisions. This material is based upon work supported by the National Science Foundation (DUE grants 1323162 and 1347740). Details about the analytic rubric reported here, and an accompanying predictive model to score new student responses, can be found here: www.msu.edu/∼aacr.