Multiplicity of Suits Law and Legal Definition

Multiplicity of suits is a term to describe a situation where more than one lawsuit exists regarding the same transaction or occurrence. The main risk with several lawsuits over the same subject matter is that different lawsuits will result in clearly contradictory results. Several actual or potential lawsuits arising out of the same transaction should be joined together in one suit and one trial.
It is a basic principle of law that multiplicity is to be avoided whenever possible, practical and fair. A judge can order cases to be consolidated upon a motion of either party or by the judge's own determination. The law strongly disfavors multiplicity of actions in order to furnish speedy relief to an injured party and to promote judicial efficiency. The principle of res judicata is one way in which courts avoid multiplicity of actions. According to res judicata, once a final judgment is reached in a lawsuit, subsequent judges who are presented with a suit that is identical to or substantially the same as the earlier one will apply the doctrine of res judicata to uphold the effect of the first judgment.