 So if one claimant lives in State X, where courts and laws are unfavourable to their claim, but another claimant lives in the more favorable jurisdiction of State Y, they may bring a class action together in State Y.Strictly speaking, State Y must not adjudicate the claim unless it is found that the applicable law is similar or identical in both states, but as a practical matter this rule is often disregarded in favor of efficient resolution of claims.Another measure particular to the U.S. is the introduction of "proportionate liability", in place of joint and several liability.