For a long time now different importance measures are put to use in reliability literature for importance ranking of events/components, an integral part of reliability analysis. Commonly used importance measures account the probability of occurrence of faults and systems structure, and ignore the effect or severity of failures which is an important factor in engineering decision making. Here a new approach is proposed by evaluating an indicator, called cost-effective indicator that accounts both the component's performance and economic aspects.

The costeffective indicator is useful in production systems where operational reliability and cost of break down are of paramount importance. Basic events/components in a fault tree are ranked as per the decreasing value of this indicator to indicate the favourable area for improvement. It is observed in the analysis that cost-effective indicator can be a handy and effective tool for inspection, maintenance and failure detection and these activities can be carried out as per the rank of the components. Upgradation of system's performance can also be done by improving components performance with relatively large values costeffective indicator.