A plaintiff begins a lawsuit by formally alleging that the defendant violated a legal duty owed to the plaintiff. Historically, the common law rules for pleading a cause of action were very complex. These rules have been greatly simplified, but have a vestigial remnant in the form of the prima facie case that a plaintiff must plead in most states. A prima facie case is a formal statement of the facts that support the plaintiff’s claim for compensation or other legal relief. For example, in a medical malpractice lawsuit, the plaintiff must allege that:

1. The defendant had a duty to treat the plaintiff in a proper manner.

2. The defendant breached this duty.

3. The breach of the defendant’s duty proximately caused the plaintiff’s injuries.

4. A certain sum of money paid to the plaintiff will compensate for the injuries.

These allegations must be supported with a recitation of facts surrounding the plaintiff’s injuries, but the plaintiff need not present expert opinion to support the prima facie case.