For using NDE data in any structural integrity assessment reasoning, it is essential to understand what is the probability that all the defects, with dimensions above a certain size, are detected. Besides it is very important to investigate if the data were correctly reported, and if the given defect size values were accurate enough.

In order to investigate this subject, a synthesis of NDE data is hereby presented. The data was collected from a digest of blind test results and from parametric studies conducted by independent institutions. The approach that has been followed is far from representing a complete statistical analysis, but provides general trends, indications, average values, and reasonable uncertainties that can be understood by the structural integrity engineer.