In Taxpayer Bill of Rights 2, Congress not only established the Office of the Taxpayer Advocate but also described its functions:

1. To assist taxpayers in resolving problems with the Internal Revenue Service;
2. To identify areas in which taxpayers have problems in dealings with the Internal Revenue Service;
3. To the extent possible, propose changes in the administrative practices of the IRS to mitigate those identified problems; and
4. To identify potential legislative changes which may be appropriate to mitigate such problems.

Read the interesting history of  TAS.