The conversion cycle spans a range of activities — product design, production planning and control, and cost accounting. Product design is a collaborative activity and can involve a number of specialists from different functional areas. Production planning and control involves planning production by optimizing factors such as customer demand, availability of materials and labor, capacity constraints, distribution constraints and storage constraints, to mention a few. Planned manufacturing activities are carried out by processing raw materials though a combination of machines and humans and creating a finished product. The cost accounting system provides data useful for evaluating production function, determining product costs and generating information for inventory valuation for external reporting purposes.