compensation is also authorised by Article 3 of Protocol No. 7 to the European Convention for the Protection of Human Rights and Fundamental Freedoms and Article 10 of the American Convention on Human Rights. Four broad approaches allow for the payment of compensation following a miscarriage of justice: tort liability in common law; claims for a breach of constitutional or human rights; statutory relief where specific legislation exists to compensate individuals who are wrongfully convicted; and non-statutory relief by way of ex-gratia schemes based on the largesse of the government. In a study of different approaches to the payment of compensation in the United States, the United Kingdom, Canada, Australia and New Zealand, only the US and the UK have statutory schemes in place. In the United States, the federal government, the District of Columbia, and 38 states have such legislation on their statutes. Twelve states have no laws requiring compensation to be paid. However, each state differs widely in regard to eligibility requirements, maximum payments, issues concerning factual innocence, the burden of proof, the behaviour of the claimant which contributed to the (now overturned) conviction, and the claimant's prior criminal history. In some states, statutes of limitations also applies. The significant benefits of statutory schemes is that they provide money and services in compensation to individuals who have been wrongfully convicted without regard to fault or blame; they do not require claimants to prove how the prosecution or police committed their mistakes. Implications The concept of miscarriage of justice has important implications for standard of review, in that an appellate court will often only exercise its discretion to correct a plain error when a miscarriage of justice (or "manifest injustice") would otherwise occur. In recent years, DNA evidence has been used to clear many people falsely convicted. The risk of miscarriages of justice is often cited as a cause to eliminate the death penalty. When condemned persons are executed before they are determined to have been wrongly convicted, the effect of that miscarriage of justice is irreversible. Wrongly executed people nevertheless occasionally receive posthumous pardons—which essentially void the conviction—or have their convictions quashed. Even when a wrongly convicted person is not executed, years in prison can have a substantial, irreversible effect on the person and their family. The risk of miscarriage of justice is therefore also an argument against long sentences, like a life sentence, and cruel prison conditions.