Parties are considered as the same if there is any privity between the parties in two actions and if their interests are similar[i].  The question of privity between parties seeking the same relief mainly arises in class actions.  In such actions, if a member of the class who already represented in the class action files an independent action as an individual to enforce his/her own right, the effect of privity on abatement of actions commonly arises.

If the privity between the plaintiffs in separate suits on the same cause of action is such that a recovery in the prior suit will bar recovery in the subsequent suit, then the identity of the parties is sufficient to meet the requirements for abatement of the second action[ii].

However, the similarity of the privity of the parties in the two suits is not sufficient if their rights and obligations are not identical and the parties are not identical legal persons[iii].

[i] Philips Elecs., N.V. v. New Hampshire Ins. Co., 295 Ill. App. 3d 895 (Ill. App. Ct. 1st Dist. 1998)

[ii] Wetzstein v. Boston & Mont. Consol. Copper & Silver Mining Co., 28 Mont. 451 (Mont. 1903)

[iii] National Cored Forgings Co. v. United States, 126 Ct. Cl. 250 (Ct. Cl. 1953)