2.2.2 Obiter dictum
In a judgment, any statement of law that is not an essential part of the ratio decidendi is, strictly speaking, superfluous. Those statements are referred to as obiter dictum. This is Latin for ‘a word said while travelling’ or ‘along the way’ (obiter dicta in the plural). Although obiter dicta statements do not form part of the binding precedent, they can be persuasive authority if taken into consideration in later cases. That is, if the judge in the later case considers it appropriate to do so (see Box 4).
Box 4 Example of obiter dictum
In the case above about the dog and the man injured by the shard of glass, one judge said that if you knew your dog had an excitable tendency or went mad in cars, then you would be liable if it caused someone harm in a predictable way (not in the freakish broken window scenario) and would have to pay compensation. The judge did not need to rule on that in the dog-and-the-car-window case, because the couple did not have a dog with a known excitable temperament. His observations were, therefore, made ‘by the way’ and thus can be referred to as an obiter dictum. In a future case involving a dog known by its owners to be excitable, a lawyer for an injured claimant could refer back to the judge’s obiter dictum in the car window case and use it as ‘persuasive’ but not ‘binding’ authority.
The division of cases into these two distinct parts is an analytical tool. Unfortunately, judges do not actually separate their judgments into the two clearly defined categories and it is up to the person reading the case to determine what the ratio is. This is a bit like listening to, or reading, a speech made by a politician or a sports team manager and trying to identify what the most important part of the speech was.
In some cases this is no easy matter, and it may be made even more difficult in cases where there are three or five judges and where each of the judges delivers their own lengthy judgment so there is no clear single ratio.