A swim lane diagram also known as cross-functional diagram or Rummler-Brache Diagrams provides a visual representation – a process map and is used in process flow diagrams. The swimlane diagram (arranged horizontally or vertically) demarcates responsibilities for sub-processes of a business process. It is a process flowchart that provides information on who does what. Each member is assigned to a lane(s) and the diagram looks like a swimming pool metaphorically. Each lanes helps visualize a particular stage, employees or departments.

A book about Improving Processes in the 1990s by Geary Rummler and Alan Brache had proposed Swim Lane Diagrams.