The mischief rule is used to interpret statutes based on the purpose and intention of Parliament rather than just the literal meaning. It examines the problem or "mischief" that the statute aims to address. The rule originated in Heydon's Case in 1584 and involves considering the law prior to the statute, the flaws in the prior law, and how Parliament intended for the new statute to remedy issues. While it provides flexibility and helps achieve parliamentary intent, critics argue it allows judges to rewrite laws and determining intention requires relying on assumptions about parliamentary purpose.