In the reliability theory, the performance of a system can be improved by different methods, such as redundancy and reduction methods. The redundancy method may not be optimal when some restrictions such as volume and weight are crucial. In the reduction method, system reliability is increased by reducing the failure rate of some of its components by a factor 0 <ρ< 1 which is called the reliability equivalence factor (REF). This article considers a new light on reliability equivalence factors in a coherent system with independent components. A closed form for ρ is obtained when the reduction method is applied on a single component of the system. Based on this, we also define a new measure of component importance. Various numerical illustrative examples are given to support the new results.

Keywords