This case study describes the development and field-testing of a research-based scoring rubric for analyzing elementary students' schoolyard habitat drawings. To justify schoolyard learning experiences in U.S. schools, teachers, program evaluators, and others need valid, reliable, and objective assessment tools for determining if, and how, these learning experiences influence students' perceptions and understandings of ecological concepts. Three different raters used the 7-item rubric to evaluate 77 drawings. A high degree of inter-rater score reliability was found and no significant differences were found between scores of different raters. To determine if the rubric could detect measurable differences in drawings made by students of different genders, academic ability levels, and ethnicities, scores were compared and analyzed by subgroup. Results indicate that it is possible to develop a quantitative, easy-to-use tool for analyzing drawings and identifying differences in students' perceptions of their schoolyard habitats. (Contains 2 figures.)