Collateral Estoppel - Related Concepts

Related Concepts

Collateral estoppel is closely related to the concept of claim preclusion, which prevents parties relitigating the same cause of action after it has been decided by a judge or jury. Res judicata (literally - that which has been decided) can be used as the term for both concepts, or purely as a synonym for claim preclusion. Under the doctrine of res judicata, a judgment on the merits in a prior suit bars a second suit involving the same parties or their privies based on the same cause of action. Under the doctrine of collateral estoppel, on the other hand, the second action is upon a different cause of action and the judgment in the prior suit precludes relitigation of issues actually litigated and necessary to the outcome of the first action.

Res judicata may be used as a defense in a second suit which involves the same claim as a prior suit, and is conclusive on all matters which were litigated as well as all matters which could have been litigated in the prior suit. In collateral estoppel the judgment is conclusive only regarding the issues which were actually litigated. In order for CE to apply, four factors must be met:

• The issues in the second suit are the same as in the first suit;
• The issues in the first suit must have been actually litigated;
• The issues in the first suit must have been actually decided;
• The issues must have been necessary to the court's judgment.

See also direct estoppel.