Patent Number: 
Section: claims

1. A method for monitoring performance of a product comprising: a design phase including:  using a design for six sigma process to design the product and generate a plurality of design for six sigma elements representing characteristics of the product, wherein said design for six sigma elements include a key control parameter, said key control parameter including a lower specified limit, an upper specified limit, and a Z value indicating how frequently the key control parameter exceeds the lower specified limit or the upper specified limit;  storing said design for six sigma elements in a design for six sigma database; and  a service phase including:  monitoring performance of the product based on the design for six sigma elements stored in the design for six sigma database, wherein monitoring includes sensing a sensed key control parameter of the product, comparing the sensed key control parameter to the key control parameter, determining if said sensed key control parameter exceeds said lower specified limit or said upper specified limit, computing a sensed Z value for said sensed key control parameter indicating how frequently the sensed key control parameter exceeds the lower specified limit or the upper specified limit, and comparing the Z value to the sensed Z value. 2. The method of  claim 1  wherein: claim 1 said design for six sigma elements include a total Z value based on a plurality of Z values; and  said monitoring includes computing a plurality of sensed total Z values for a plurality of sensed key control parameters and comparing the total Z value to the sensed total Z value. 3. The method of  claim 1  wherein: claim 1 said design for six sigma elements include at least one tool used in the design phase to derive the key control parameter. 4. The method of  claim 1  wherein: claim 1 said design for six sigma elements include transfer functions used in the design phase to describe the product response to input data. 5. The method of  claim 1  wherein: claim 1 said design for six sigma elements include test results obtained during the design phase, said test results including measurements of key control parameters.