Congressional Oversight of Policy Implementation

Describe in detail one Congressional activity oversight method (tool) and how that process is used to specifically provide oversight over policy implementation.

To answer this question, give an example of the method described. Was that method successful? Why or why not? Take into account that congressional oversight of policy implementation and administration has occurred throughout the history of the United States government under the Constitution. Oversight consists of the review, monitoring, and supervision of operations and activities and takes a variety of forms and utilizes various techniques.