The Government Accountability Office (formerly General Accounting Office) is "the investigative arm of Congress" and audits the performance of agencies and offices in carrying out their duties (including their various programs) to ensure their effectiveness and efficiency.
Many of the GAO reports of their investigations are listed in the Library catalog, but they are also searchable (and readable) online from the GAO web site. The search box is at the top right of the web page, and a browse by topic option is on the left side of the "Reports & Testimonies" web page. Examples below are: a cover image of a GAO "blue book" report and its record in the Lbrary catalog, and on the GAO web site.
The record for this GAO "blue book" report in Books, media and more (UW Whitewater), the Library catalog portion of Research@UWW, with link to the report online.