Tax noncompliance is a range of activities that are unfavorable to a state's tax system. This may include tax avoidance, which is tax reduction by legal means, and tax evasion which is the criminal non-payment of tax liabilities. The use of the term 'noncompliance' to refer to tax avoidance, however, is not universal or standard, and similar terms are also used differently by different authors. For example, in the United States the use of the term 'noncompliance' often refers only to illegal misreporting. Laws known as a General Anti-Avoidance Rule (GAAR) statutes which prohibit "tax aggressive" avoidance have been passed in several developed countries including the United States (since 2010), Canada, Australia, New Zealand, South Africa, Norway and Hong Kong. In addition, judicial doctrines have accomplished the similar purpose, notably in the United States through the "business purpose" and "economic substance" doctrines established in Gregory v. Helvering. Though the specifics may vary according to jurisdiction, these rules invalidate tax avoidance which is technically legal but not for a business purpose or in violation of the spirit of the tax code. Related terms for tax avoidance include tax planning and tax sheltering.