A bright-line rule or bright-line test is a clear, simple, and objective standard which can be applied to judge a situation. In other words, it is a judicial rule that helps to resolve ambiguous issues by setting a basic standard that clarifies the ambiguity and establishes a simple response. The purpose of a bright-line rule is to produce predictable and consistent results in its application. Bright-line rules are usually standards established by courts in legal precedent or by legislatures in statutory provisions.
For example, in American statutory rape laws, the age of the victim and the age of the accused are the only relevant factors determinative of guilt or innocence. Because it is a bright-line rule, there is no balancing test to examine factors such as mistake of the accused, the misrepresentation of age by the minor, or the minor's consent to sexual intercourse.