All tax administrations seek to maximize the overall level of compliance with tax laws. Compliance improvement plans (CIPs) are a valuable tool for increasing taxpayers’ compliance and boosting tax revenue. This note is intended to help tax administrations develop a CIP, by providing guidance on the following issues: (1) how to identify and rate compliance risks; (2) how to treat risks to achieve the best possible outcome; and (3) how to measure the impacts that treatments have had on compliance outcomes.

This report is the ninth edition of the OECD's Tax Administration Series. It provides internationally comparative data on aspects of tax systems and their administration in 59 advanced and emerging economies.

This paper addresses core challenges that all tax administrations face in dealing with noncompliance—which are now receiving renewed attention. Long a priority in developing countries, assuring strong compliance has acquired greater priority in countries facing intensified revenue needs, and is critical for fairness and statebuilding. Series: Policy Papers

This FAD mission reviewed recent progress to improve tax administration and identified areas of priority tax administration modernization for 2019–23. The MEF has been implementing the RMS, a major component of which is the strengthening of the administration of the GDT. As the RMS ends in 2018, the MEF is now developing the next phase of reforms to strengthen the revenue system of Cambodia over the period 2019 to 2023. The GDT has made significant progress with implementing the RMS measures under its responsibility, and achieved extremely positive revenue growth and collections. The GDT has completed 71 out of the 86 RMS tax administration measures; the remaining 15 are under active progress. Since 2012, the GDT has routinely exceeded its revenue targets, and year-on-year revenue growth has far exceeded the annual levels of economic growth. Cambodia’s 2017 tax-to-GDP ratio of 17.2 percent is now comparable with many regional countries.