In a speech to a conference of government trade officials, Angel Gurra, secretary general of the Organization

Question:

In a speech to a conference of government trade officials, Angel Gurría, secretary general of the Organization for Economic Co-operation and Development, made the following observation: "As goods and services cross borders several times at different stages of processing, conventional trade statistics may not tell the whole story."
a. What does Gurría mean by "conventional trade statistics"?
b. Why might conventional trade statistics no longer be as reliable as they once were?
c. What difficulties might the problems with trade statistics cause for policymakers?