recently, focused its attention. In recent years, the types of military engagements faced and anticipated have changed quite dramatically. As a consequence, the importance of placing increased emphasis on the development of highly reliable systems has grown. Speakers and discussants strongly confirmed the need for improved reliability growth management through frequent and thorough testing and inspection and through the application of global, cross-disciplinary strategies for achieving and surpassing reliability growth targets.

It was pointed out by more than one speaker that at present, defense systems regularly fail to satisfy their operational suitability requirements in the field. (Suitability encompasses reliability and related measures, including maintainability and availability.) As a result, DoD is spending far too much for system redesigns late in system development, and for spares management and system maintenance (and also system redesign) after the system has been fielded. DoD systems also are frequently submitted for operational testing before they are sufficiently mature with respect to system reliability. For example, it was pointed out that 80 percent of Army systems failed to achieve even half of their requirements for mean time to failure in operational test (Defense Science Board, 2000).

Mention was made of a number of methods currently used in industrial applications of system development and reliability growth management that are not being used in defense system development, but appear to be relevant to the latter systems. First, early assessment of (operational) reliability could play an important role in improving system design, as opposed to current primary use in supporting the milestone decision process. Second, little or no use is currently made of test or field failure data to (1) support a better understanding of system life-cycle costs; (2) help determine how failure modes escaped detection during developmental or operational testing; or (3) relate the reliability of systems and failure modes in operational test to the reliability of systems and failure modes in developmental test, which could support methods for combining information from developmental and operational testing (as discussed earlier). The estimation of system life-cycle costs was noted as a particularly important use of field performance data. (As mentioned above, the increased accessibility of such data to support this type of analysis would require the institution of a data archive.) Third, it was noted that it is typical in reliability growth modeling for defense systems—used to predict system reliability in the future (e.g., to ascertain when it would be appropriate to enter operational test)—to make no attempt to model



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