In the past I discussed multidistrict litigation (MDL) and when it is strategically advantageous. MDL is similar to a class action, but distinct. MDL is appropriate when there are one or more common questions of fact involved in different lawsuits that are pending in different judicial districts. In such cases, the actions may be transferred to any district for consolidated pretrial proceedings.
Certification as a class action requires common questions of fact -- or law -- and more. It requires a proposed class too large to join all the members in the pending lawsuit, the same or similar claims and defenses among the class members, and the lead plaintiffs must fairly and adequately represent the entire class's interests. A class action also requires either the risk of inconsistent or preclusive results in other lawsuits if the class is not certified, or that the common questions of law or fact predominate over those affecting only individual members.
The latest NCAA concussion litigation is a good example of a case where consolidation for MDL is sought. The first case was filed in 2011, and several more have been filed this year.