This book serves as a toolkit on risk-based audits and brings together country experiences for implementing risk-based audit systems. Risk management is an important element of effective and efficient compliance management in revenue administration. It is impossible for any revenue administration to control and check every single taxpayer, and an unnecessary waste of scarce enforcement resources on routinely examining low-risk, compliant taxpayers. The opportunity costs for such roving examinations are high. Just as a private business allocates its resources to areas they feel have the most potential for generating revenues and profits, a modern revenue administration selects cases for audits using methods focused on high-risk taxpayers. This targeted focus is likely to raise higher revenue and, arguably, provide a stronger deterrence for non-compliance. Risk management techniques should not be considered to be confined to the selection of tax audit cases. It is part of a holistic and cooperative approach to enhance compliance. This is dramatically changing the way revenue administrations and taxpayers interact with each other.The effectiveness of a risk-based compliance management has been enabled by, and depends fundamentally on, the use of automated systems to: (1) gather third-party information and match with taxpayer reporting using reliable databases and a unique taxpayer identification number; (2) undertake selective checks based on risk analysis; (3) standardize payment processes (e.g., payments through banks) and accounting requirements; (4) provide assurance that the legislation and procedures are being applied uniformly; and (5) provide adequate, timely information to support management decision making and tax policy formulation.