The document provides guidance on structuring impact case studies for Australian National Health and Medical Research Council (NHMRC) grant applications. It discusses the five key elements of impact: 1) knowing your pathway to impact, 2) mapping outputs, outcomes and impacts, 3) using a problem statement, 4) backing statements with evidence, and 5) showing rather than telling. Impact case studies for NHMRC grants should follow a backward pathway structure with three fields addressing the reach and significance of impact, the research program's contribution, and the applicant's role. The document provides examples and tips for writing each field effectively with evidence to support statements about impact.