Short answer: class actions are when many people join one case for identical outcomes, and mass torts are groupings of similar individual cases where one decision can lead to unique outcomes.
A class action lawsuit involves a large group of people that have experienced extremely similar outcomes stemming from the same cause, such as a defective product. Because the cases must meet the strict guidelines of the class action, they are presented under one plaintiff. The final compensation is divided evenly across the entire class.
In a mass tort case, individual experiences may vary, as in a negligently caused fire that destroys one person’s home, another’s business, and a third person’s health. Even though a large number of people have been affected, the variations from case to case are broad and distinct, so each plaintiff is considered independently when it comes to settlement amounts.