A criticality analysis is a way to determine which systems and assets are most essential, in order to set priorities for further reliability initiatives and deeper analysis. This analysis is a means of examining and understanding available data; collecting and preserving organizational knowledge; understanding the effect of a failure of a system or some part or whole of an asset; evaluating the severity of the resulting consequences; ascribing a likelihood to the failure occurring; and then organizing all of this information to compare and rank the results.

Tip from "Criticality Analysis Made Simple" by Tacoma Zach