This study examines the current state of assessment of computational thinking (CT) programming in public libraries in the United States. In particular, this study identifies the assessment tools and strategies that public library staff use to evaluate the success of CT youth programming, as well as how they share these assessment results, what they share, and with whom. This work also examines the perceptions of library staff on assessment of CT learning in libraries. Through our work, we highlight the need for a change of mindset in the perception of library staff toward assessment of CT learning in libraries. We also demonstrate the need for suitable assessment strategies to measure learning in CT programming in libraries beyond attendance and retention, that communicate to library staff on how they can revise their programs and to share their program impact with library stakeholders who make decisions on budget and resource allocations.