High Reliability Electronic Parts as Justified System Cost Elements

The planned use of premium electronic parts in a forthcoming system is a logical means for assuring failure-free operation comensurate with the best state-of-the-art. However, an over-all analysis of the value of premium parts must show the net worth of improved system performance to more than offset the added initial parts cost. These costs may be in higher procurement costs, added test and evaluation, or more intangible investments. At the outset, a system-production strategy must establish the best level of investment in such features, based upon a conviction that the ``impact'' upon reliability improvement will justify the added initial costs. This paper treats the difficult problem of evaluating the system reliability ``impact'' introduced by increased parts reliability. The necessity for an early investment strategy will limit the level of analytical sophistication available for predicting reliability. Thus, it is useful to examine the validity of reliability ``parts population analyses'' as first-order justifications for investing in high reliability parts for complex electronic systems.