A responsibility assignment matrix (RAM) is a chart showing the relationship between people and elements of work. It is created by combining two breakdown structures the work breakdown structure with the organisational breakdown structure.
If required, the work breakdown structure could be replaced with a product breakdown structure.
The matrix illustrates the allocation of activities, work packages or products to people, organisations or third parties. The RAM can be populated with information regarding whether someone is responsible or accountable, or should be consulted or informed. For this reason it is often known as a RACI chart.