... a measure of the ability of a system to satisfy its intended operational uses when called upon to do so. System effectiveness is a composite view of how the system performs under anticipated environmental conditions, the reliability and maintainability of system parts and components, and the ability to produce, distribute, support, train, operate and dispose of the system throughout its life cycle -- SEI:SA-CMM
... the probability that the system can successfully meet an operational demand within a given time when operated under specified conditions -- System Effectiveness Models: An Annotated Bibliography”, IEEE Transactions of Reliability, Vol. R-29, No. 4, October 1980, pp 295-304
... a measure of the degree to which an item can be expected to achieve a set of specific mission requirements and which may be expressed as a function of availability, dependability and capability -- ARINC Res. Corp., Reliability Engineering. Englewood Cliffs, NJ: Prentice Hall 1964
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