This comprehensive survey on the tested performance of steel deck diaphragms indicates the expected ductility and overstrength in these critical building systems. Both bare deck diaphragms and decks with concrete fill are summarized. An approach is proposed for extending the experimental results to establish seismic capacity modification factors appropriate for diaphragms based on the tested performance. The report is available from the Cold-Formed Steel Research Consortium permanent library space: https://jscholarship.library.jhu.edu/handle/1774.2/40633.