Legal Malpractice and Breach of Fiduciary Duty
Many people do not understand the difference between legal malpractice and breach of fiduciary duty.
Legal malpractice arises when an attorney owes someone a duty of care and, by an act or omission, the attorney's conduct breaches that duty of care and causes that person cognizable harm. While the "person" harmed is typically a client, an attorney-client relationship is not required and legal malpractice claims often arise in "non-client" situations as long as the attorney owes the harmed person a duty of care (e.g., a beneficiary to a will).
Legal malpractice, just like medical malpractice, refers to conduct that "falls below the standard of care." That is why, typically, expert witness testimony is required in malpractice actions -- i.e., to establish the "standard of care." Of course, some conduct is so obviously below the standard of care that expert testimony is not required (e.g., missing a statute of limitation).
What about breach of fiduciary duty?
Breach of fiduciary duty arises when there is a "special relationship" between an attorney and, typically a client, where trust or control over another's affairs are vested with an attorney. The major difference between legal malpractice and breach of fiduciary duty lies in the nature and scope of the applicable "duty."
A fiduciary duty is the highest standard of care, so it is a qualitively greater duty than the "ordinary" duty of care applicable to malpractice. Fiduciary duties not only require duties of utmost care, but also duties of good-faith, loyalty and trust.