Activity-based costing is an accounting method that recognizes the relationship between product costs and a production activity, such as the number of hours of engineering or design activity, the cost...Activity-based costing is an accounting method that recognizes the relationship between product costs and a production activity, such as the number of hours of engineering or design activity, the costs of the set up or preparation for the production of different products, or the costs of packaging different products after the production process is completed.