How much field work do NSA investigators do?

Despite how the movies portray the National Security Agency, it does not have agents or investigators working in the field. The NSA is the world's largest employer of mathematicians. Most of these employees work to break the encryption codes used by other countries and organizations hostile to the United States, and to devise codes for the United States to use for its own data and communications.

The NSA intercepts and analyzes communications from all over the world. When it discovers information that may be of interest to one of the many intelligence agencies in the United States, it passes it along to them for further action.

When the NSA does have reason to obtain information "in the field," the information gathering is usually performed by FBI agents in the United States, and CIA case officers abroad.