It is preferable to use TDPU (total # of defects per unit) instead of the Process Yield, when we have reason to expect wide variance in the # of defects among individual defective units - such as in a new process, or with a new supplier or new workers. While comparing two processes making identical products, one long running and the other relatively new, why should we prefer using TDPU over Process Yield to guage ouput and process quality? Primarily, because doing so would let us see the process yields of different processes Primarily, because doing so would let us see if one process has a greater flow rate compared to the other Primarily, because doing so would let us see possible deeper quality differences among different processes that may be apparently of identical quality, i.e.have the same Process Yield