Government Auditing Standards

The Generally Accepted Government Auditing Standards, commonly referred to as the "Yellow Book", are produced in the United States by the Government [Accountability Office].
The standards apply to both financial and performance audits of government agencies. Five general standards are included:

Independence
Due care
Continuing professional education 80 hours every 2 years, 24 hours directly related to government auditing
Supervision
Quality control

The Yellow Book standards are used by auditors who examine the federal government, including the Government Accountability Office, various offices of inspectors general, and others. Many local government performance auditors also use the yellow book standards. In addition, CPA firms that perform local government financial audits that include an A-133 "single audit" must follow yellow book standards.
In addition to financial audits, the Yellow Book standards cover Performance Audits, which evaluate the performance of a program or project against defined objectives, such as objectives for efficiency and effectiveness.
The Yellow Book standards provide auditors with a framework for behaving ethically. It outlines five key principles:

The public interest
Integrity
Objectivity
Proper use of government information, resources, and positions
Professional behavior

Other government auditing standards, used by supreme audit institutions

The International Organization of Supreme Audit Institutions has developed the INTOSAI Auditing Standards