The EPD model is how Engineering, Product, and Design collaborate to deliver value to the company. Each of one of these organization plays a role within the model1:
Product - Identifying, de-risking, and preparing product opportunities for the company Engineering - Sequences work, staffs appropriately, and implements the product design changes Design - Designs and scopes product changes so that those changes integrates with all historical decisions
Jack Danger likes to analogize this to providing a cockpit with which the CEO can pilot the company1. Product provides the instruments, design provides the fuselage, and engineering provides the thrust. Notably the relationship between these parties is a “peer” relationship where they are playing a role, not “piloting” the airplane.
1. Danger, J. Executive Engineering: Practical Engineering Theory for Software Leaders. (The Technical Executive, 2024).