A method for evaluating the operation of a continuous process plant uses operational data. The operational data includes data points representing the quantity of a substance processed by the continuous process plant during a plurality of time periods. The quantity of substance processed during these time periods is compared to a goal value. A reliability score is calculated. A banked opportunity score is calculated. An equivalent lost stream days score is calculated. The average quantity processed during periods that equaled or exceeded the goal is calculated. The average quantity processed during periods that were below the goal is calculated. The components of the equipment or machinery of the continuous process plant are classified and correlated to the quantity of lost opportunity. The scores are reported. The scores are also compared to historical data.