Standard of Proof

Typically, to prevail in a legal malpractice case, a plaintiff must prove all of the following:

The existence of an attorney-client relationship;
Negligence in the legal representation of the plaintiff;
That the negligence was a proximate cause of an injury;
The fact and extent of the injury alleged.

As malpractice laws vary by state, your state may not adhere to the elements listed above.

Proving Legal Malpractice

A plaintiff must prove an attorney-client relationship existed. Absent an attorney-client relationship, the lawyer doesn't have any duty to the client, and there is no basis for a legal malpractice action.

A plaintiff must establish the standard of care which governed the legal representation, and show that the attorney violated that standard of care. Because legal representation is often complex, it is often necessary to use an expert witness to establish the controling standard of care, and to prove how the lawyer violated that standard of care.

Once those elements are satisfied, is necessary to demonstrate that the plaintiff suffered an injury as a proximate result of the lawyer's negligence. That is, that the injury followed from the lawyer's misconduct. For example, where a lawyer fails to make an evidentiary objection which would have kept a murder weapon out of evidence, a criminal defendant may have a case for legal malpractice - but if the defendant confessed to the murder, left fingerprints all over the victim's house, and was caught while trying to use the victim's credit cards, the defendant won't be able to demonstrate that the lawyer's mistake affected the outcome of his case, and thus won't be able to show that the injury resulted from the negligence. Similarly, if the connection between the alleged act of negligence and the harm suffered is speculative or extremely attenuated, it may not support a malpractice claim - the injury suffered must ordinarily be a reasonably foreseeable consequence of the attorney's negligence.

A plaintiff must establish that damages actually were suffered as a result of the legal malpractice, and the nature and amount of those damages. Even if all other elements of a malpractice case are established, if the plaintiff cannot show that any damages resulted from the legal malpractice the lawyer will typically be entitled to a dismissal of the case.