"The Every Student Succeeds Act" encourages educators to use school improvement strategies backed by rigorous research. This snapshot, based on national surveys administered in 2018, describes what guidance states provided on improvement strategies and how districts selected such strategies in lowest-performing schools. Most states pointed districts and schools to evidence on improvement strategies, but few required schools to choose from a list of approved strategies. In turn, most districts reported that evidence of effectiveness was "very important" when choosing improvement strategies, but the evidence districts relied on probably varies in quality. [The data presented in this snapshot come from state and district surveys administered in 2017-18 (between April and September 2018) as part of the Study of "Implementation of Title I and Title II-A Program Initiatives: Results from 2013-14. NCEE 2017-4014" (ED572281).]