A dictum is an opinion given by a judge that is not essential to the final ruling of the case. Dicta, the plural form of dictum, may be voluntarily made in dissent or in support of the court's findings. In many jurisdictions, a dictum has no bearing on the decision, or holding, made by the court. It may be highly regarded because of the standing of the judge asserting the opinion, but they may or may not have authority under the doctrine of precedent, or stare decisis. Although it is sometimes cited in legal argument, a dictum might not be binding on other courts when deciding similar issues.
The doctrine of stare decisis, or "to stand by things decided," typically makes it necessary for courts to follow previous judicial decisions, or precedent, made under similar legal points and facts. When courts issue an official decision, they typically cite precedent. The assertion of opinions unrelated to the issues of the case are not typically binding on other courts and are not usually considered to be part of the holding.
In the United States, there are several recognized forms of dictum that may not be binding, but can be persuasive. Dictum proprium is an opinion given by a judge that is not necessarily shared by the rest of the court and is not essential to the decision. Simplex dictum is an unproven statement of opinion, while obiter dictum may be something said in passing that is not essential to the ruling, but may be considered persuasive. Judicial dictum may involve a comment regarding an issue argued by counsel, but not essential to the ruling. Gratis dictum includes discussion or rules that do not apply to the case currently being decided.
In the United Kingdom, a dictum is sometimes defined as any statement made that is considered part of the court's judgment. These statements may have authority, even if they are merely persuasive. The UK may consider ratio decidendi, or the statements making up the rationale for the decision, to be as binding as precedent. Ratio decidendi takes into account the legal, moral, social and political principles that the court used to come to its holding.
Whether or not a statement is considered binding under ratio decidendi or merely persuasive dictum might depend on several factors. These may include the rank and authority of the court considering the matter, the clout of the judge and the number of judges who agreed and disagreed with the holding of the case. The basis of ratio decidendi typically involves an analysis of the essential legal points that the parties to a dispute are bound by. All other comments that are found to be non-essential to the court's ruling usually do not fall within the doctrine of stare decisis and are not typically binding.