The purpose of an equipment criticality ranking (ECR) study is to identify and address potential risk associated with the operation of processing facilities.  Failure scenarios are identified, risk-ranked, and risk quantified with consideration given to safeguards that protect against the scenarios.  Equipment criticality rankings are a sum of risk from applicable scenarios.  Safeguards are identified and prioritized based on the amount of risk reduction they provide.

ECR study data facilitate safeguard analysis, a technique used to evaluate benefit-to-cost (BTC) ratios for risk reduction programs and to monitor safeguard effectiveness.  Safeguards should be maintained or implemented only where safeguard costs give commensurate returns in the way of reduced facility exposure.  An enterprise should reduce costs by using BTC analysis to identify and eliminate support programs with low BTC ratios.

Safeguard effectiveness is a measure of actual versus perceived risk reduction for safeguards credited with reducing risks.  Automated exception reporting can be used to monitor safeguard effectiveness and to notify personnel when intervention is required to intercept a potential loss before it happens