The Supreme Court's recent decision in the Wal-Mart sex-descrimination suit demonstrates the importance of 'commonality' in class actions.  Not to mention that the decision is a good example of why MDLs, free from such 'roadblocks', are the new class actions.  Because MDLs are not regulated in the way class actions are, such a review for lack of commonality reasonably would never occur.

The plaintiffs' case against Wal-Mart was based on an alleged pattern of descrimination in the form of paying women workers less than thier male counterparts and providing them fewer opportunities.  In the end, the allegations were not enough to permit the three named plaintiffs to represent a class of 1.6 million.

Merely showing that Wal-Mart's policy of descrimination has produced an overall sex-based disparity does not suffice. - Justice Scalia.