© 2019 Copyright held by the owner/author(s). Publication rights licensed to ACM. We report on the analysis of responses about the benefits of educational Fab Labs and Makerspaces (FLMs) and about claims of student growth and learning in these spaces. We review related literature on assessment in FLMs and on efforts to develop frameworks. Methods of the the current study include the design of the FabLearn workshop, where responses were elicited from practitioners, and mixed-methods analyses of those responses. Results, in the form of the coding guides, are presented, followed by a discussion of the construct categories, alignment between benefits and claims codes, and consequences for coherent assessment in FLMs.