In "Using Learning Progressions to Design Vertical Scales that Support Coherent Inferences about Student Growth" (hereafter ULR), Briggs and Peck suggest that learning progressions could be used as the basis of vertical scales with naturally benchmarked descriptions of student proficiency. They propose and provide a single example of a vertical scale that assigns examinees to progressive "levels" described by "attributes: what students know and can do." This is an extremely positive suggestion that could be elaborated for even greater potential utility if integrated with the domain-sampling idea of growth that underlies contemporary vertical scales.