Alyeska Pipeline Service Co. in recent years has conducted numerous in-line inspections (ILIs) of its 800-mile system. Sites most affected by external corrosion have been identified, excavated, and evaluated based on subsequent field measurements of the corrosion. The extensive database that resulted has proven invaluable for evaluating the performance of ILI surveys. This database has provided information necessary for comparing the performance of different pigs. It has also been useful for applying knowledge obtained from past excavations to a decision-making process for identifying future excavation sites or candidate locations for alternative remediation such as cathodic protection upgrades. The methods used in the Alyeska program, and presented here, permit one to optimize available data and compare them statistically with measurements of actual external corrosion. Results of the analyses can be used to quantify the performance of past and future inspections (detection, accuracy, etc.) and to quantify the added value of additional excavations and inspections. The approach used to assess in-line inspection data as described here can be adapted by most pipeline operators to their particular situations.