Cooper and Chew (1996) have explained that target costing is not an exact science. They emphasized that it depends on credible data and on managers who have the courage to make difficult judgments. However, 78 percent of the manufacturers using this method believe that target costing is an iterative process that cannot be separated from the ordinary push-and-pull of the car design process. Almost 60 percent expressed the view that targets evolve as manufacturing teams seek to balance new car functionality, price, volumes, capital investment and costs. Others (35 percent) simply explained that since target costing is integrative, responsibility for achieving targets must be shared across functions. Over 70 percent agreed that to use target costing effectively, manufacturers must treat their component suppliers and dealers as partners both during the car design process and when the car cost targets are set.