In law, a class action or a representative action is a form of lawsuit where a large group of people collectively bring a claim to court. This form of collective lawsuit originated in the United States and is still predominately a US phenomenon, at least the US variant of it. However, in several European countries with civil law (as opposed to the Anglo-Saxon common law principle, which is used by US courts), changes have in recent years been made that allow consumer organisations to bring claims on behalf of large groups of consumers.
Class action lawsuits may be brought in federal court if the claim arises under federal law, or if the claim falls under 28 USCA § 1332 (d). Under § 1332 (d) (2) the federal district courts have original jurisdiction over any civil action where the amount in controversy exceeds $5,000,000 and either 1. any member of a class of plaintiffs is a citizen of a State different from any defendant; 2. any member of a class of plaintiffs is a foreign state or a citizen or subject of a foreign state and any defendant is a citizen of a State; or 3. any member of a class of plaintiffs is a citizen of a State and any defendant is a foreign state or a citizen or subject of a foreign state. Nationwide plaintiff classes are possible, but such suits must have a commonality of issues across state lines. This may be difficult if the civil law in the various states have significant differences. Large class actions brought in federal court frequently are consolidated for pre-trial purposes through the device of multidistrict litigation (MDL). It is also possible to bring class action lawsuits under state law, and in some cases the court may extend its jurisdiction to all the members of the class, including out of state (or even internationally) as the key element is the jurisdiction that the court has over the defendant.
Typically, federal courts are thought to be more favorable for defendants, and state courts more favorable for plaintiffs. Many class action cases are filed initially in state court. The defendant will frequently try to remove the case to federal court. The Class Action Fairness Act of 2005 increases defendants' ability to remove state cases to federal court by giving federal courts original jurisdiction for all class actions with damages exceeding $5,000,000, exclusive of interest and costs. It should be noted, however, that the Class Action Fairness Act contains carve-outs for, 'inter alia', shareholder class action lawsuits covered by the PSLRA and those concerning internal corporate governance issues (the latter typically being brought as shareholder derivative actions in the state courts of Delaware, the state of incorporation of most large corporations).
The procedure for filing a class action is to file suit with one or several named plaintiffs on behalf of a proposed class. The proposed class must consist of a group of individuals or business entities that have suffered a common injury or injuries. Typically these cases result from an action on the part of a business or a particular product defect or policy that applied to all proposed class members in a uniform manner. After the complaint is filed, the plaintiff must file a motion to have the class certified. In some cases class certification may require additional discovery in order to determine if the proposed class meets the standard for class certification.
Upon the motion to certify the class, the defendants may object to whether the issues are appropriately handled as a class action, to whether the named plaintiffs are sufficiently representative of the class, and to their relationship with the law firm or firms handling the case. The court will also examine the ability of the firm to prosecute the claim for the plaintiffs, and their resources for dealing with class actions.
Due process requires in most cases that notice describing the class action be sent, published, or broadcast to class members. As part of this notice procedure, there may have to be several notices, first a notice giving class members the opportunity to opt out of the class, i.e. if individuals wish to proceed with their own litigation they are entitled to do so, only to the extent that they give timely notice to the class counsel or the court that they are opting out. Second, if there is a settlement proposal, the court will usually direct the class counsel to send a settlement notice to all the members of the certified class, informing them of the details of the proposed settlement.
In federal civil procedure law, which has generally been accepted by most states (through adoption of state civil procedure rules paralleling the federal rules), the class action must have certain definite characteristics: (1) the class must be so large as to make individual suits impractical, (2) there must be legal or factual claims in common (3) the claims or defenses must be typical of the plaintiffs or defendants, and (4) the representative parties must adequately protect the interests of the class. In many cases, the party seeking certification must also show (5) that common issues between the class and the defendants will predominate the proceedings, as opposed to individual fact-specific conflicts between class members and the defendants and (6) that the class action, instead of individual litigation, is a superior vehicle for resolution of the disputes at hand.
First, aggregation can increase the efficiency of the legal process, and lower the costs of litigation.
In cases with common questions of law and fact, aggregation of claims into a class action may avoid the necessity of repeating "days of the same witnesses, exhibit and issues from trial to trial." Jenkins v. Raymark Indus. Inc., 782 F.2d 468, 473 (5th Cir. 1986) (granting certification of a class action involving asbestos).
Second, a class action may overcome "the problem that small recoveries do not provide the incentive for any individual to bring a solo action prosecuting his or her rights." Amchem Prods., Inc. v. Windsor, 521 U.S. 591, 617 (1997) (quoting Mace v. Van Ru Credit Corp., 109 F.3d 388, 344 (7th Cir. 1997)). "A class action solves this problem by aggregating the relatively paltry potential recoveries into something worth someone’s (usually an attorney’s) labor." Amchem Prods., Inc., 521 U.S. at 617 (quoting Mace, 109 F.3d at 344). In other words, a class action ensures that a defendant who engages in widespread harm but does so minimally against each individual plaintiff must compensate those individuals for their injuries. For example, thousands of shareholders of a public company may have losses too small to justify separate lawsuits, but a class action can be brought efficiently on behalf of all shareholders. Perhaps even more important than compensation is that class treatment of claims may be the only way to impose the costs of wrongdoing on the wrongdoer, thus deterring future wrongdoing.
Third, in "limited fund" cases, a class action ensures that all plaintiffs receive relief and that early-filing plaintiffs do not raid the fund (i.e., the defendant) of all its assets before other plaintiffs may be compensated. See Ortiz v. Fibreboard Corp., 527 U.S. 815 (1999). A class action in such a situation centralizes all claims into one venue where a court can equitably divide the assets amongst all the plaintiffs if they win the case.
Finally, a class action avoids the situation where different court rulings could create "incompatible standards" of conduct for the defendant to follow. See Fed. R. Civ. P. 23(b)(1)(A). For example, a court might certify a case for class treatment where a number of individual bond-holders sue to determine whether they may convert their bonds to common stock. Refusing to litigate the case in one trial could result in different outcomes and inconsistent standards of conduct for the defendant corporation. Thus, courts will generally allow a class action in such a situation. See, e.g., Van Gemert v. Boeing Co., 259 F. Supp. 125 (S.D.N.Y. 1966).
Whether a class action is superior to individual litigation depends on the case, and is determined by the judge's ruling on a motion for class certification. The Advisory Committee Note to Rule 23, for example, states that mass torts are ordinarily "not appropriate" for class treatment. Class treatment may not improve the efficiency of a mass tort because the claims frequently involve individualized issues of law and fact that will have to be re-tried on an individual basis. See Castano v. Am. Tobacco Co., 84 F.3d 734 (5th Cir. 1996) (rejecting nationwide class action against tobacco companies). Mass torts also involve high individual damage awards; thus, the absence of class treatment will not impede the ability of individual claimants to seek justice. See id. Other cases, however, may be more conducive to class treatment.
The preamble to the Class Action Fairness Act of 2005, passed by the United States Congress, found:
Class-action lawsuits are an important and valuable part of the legal system when they permit the fair and efficient resolution of legitimate claims of numerous parties by allowing the claims to be aggregated into a single action against a defendant that has allegedly caused harm.
Class members often receive little or no benefit from class actions. Examples cited for this include large fees for the attorneys, while leaving class members with coupons or other awards of little or no value; unjustified awards are made to certain plaintiffs at the expense of other class members; and confusing notices are published that prevent class members from being able to fully understand and effectively exercise their rights.
For example, in the United States, class lawsuits sometimes bind all class members with a low settlement. These "coupon settlements" (which usually allow the plaintiffs to receive minimal benefit such as a small check or a coupon for future services or products with the defendant company) are a way for a defendant to forestall major liability by precluding a large number of people from litigating their claims separately, to recover reasonable compensation for the damages. However, existing law requires judicial approval of all class action settlements, and in most cases class members are given a chance to opt out of class settlement, though class members, despite opt-out notices, may be unaware of their right to opt-out because they did not receive the notice, did not read it, or did not understand it.
The Class Action Fairness Act of 2005 addresses these concerns. Coupon Settlements may be scrutinized by an independent expert before judicial approval in order to ensure that the settlement will be of value to the class members. 28 U.S.C.A. 1712(d). Further, if the action provides for settlement in coupons, the attorney must take a corresponding part of his fee in coupons. 28 U.S.C.A. 1712(a).
Where both the plaintiffs and the defendants have been organized into court-approved classes, the action is called a bilateral class action.
Because mass actions operate outside the detailed procedures laid out for class actions, they can pose special difficulties for both plaintiffs, defendants, and the court. For example, settlement of class actions follows a predictable path of negotiation with class counsel and representatives, court scrutiny, and notice. There may not be a way to uniformly settle all of the many claims brought via a mass action. Some states permit plaintiff's counsel to settle for all the mass action plaintiffs according to a majority vote, for example. Other states, such as New Jersey, require each plaintiff to approve the settlement of that plaintiff's own individual claims.
The Austrian Parliament has unanimously requested the Austrian Federal Minister for Justice to examine the possibility of new legislation providing for a cost-effective and appropriate way to deal with mass claims. Together with the Austrian Ministry for Social Security, Generations and Consumer Protection, the Justice Ministry opened the discussion with a conference held in Vienna in June, 2005. With the aid of a group of experts from many fields, the Justice Ministry began drafting the new law in September, 2005. With the individual positions varying greatly, a political consensus could not be reached.
The president of the French Supreme Court recently declared that "class actions are inescapable."
Nevertheless, the bill was withdrawn in January 2007 at the request of Minister of Health Xavier Bertrand.
See also Class Action Italia, Dalle origini ad oggi

Recent changes to Spanish civil procedure rules include the introduction of a quasi-class action right for certain consumer associations to claim damages on behalf of unidentified classes of consumers. The rules require consumer associations to represent an adequate number of affected parties who have suffered the same harm. Also any judgment made by the Spanish court will list the individual beneficiaries or, if that is not possible, conditions that need to be fulfilled for a party to benefit from a judgment.