Legal Malpractice happens when an attorney has not provided what's known to be accepted or good legal practicing. Usually this means that there could have been a better outcome for the client or a more positive result from the clients' case. It is not to say, however, that the client has been damaged by the attorney's practice.
Attorneys are held to a certain standard of professional performance. In New York, this standard is the same for all attorneys, upheld by the courts. When an attorney does not fully exercise his skill in a law assignment, the attorney is thus not meeting the set standard of care and professional performance to which he is required.
In a Legal Malpractice case, one necessary factor is the attorney-client relationship. The plaintiff must have retained the attorney (creating the attorney-client relationship) in order to sue for legal malpractice. However, a few exceptions exist, though they are very limited. In most cases, the relationship between the attorney and the plaintiff requires that the attorney owes the plaintiff a service. To prove that malpractice occurred, it is necessary that the plaintiff provide either a written retainer showing the attorney was hired, or proof that the attorney appeared on the client's behalf or worked on the case in some way. Litigation provides proof of representation (clearly), but with representation, the indications are not so exact. Either way, the plaintiff must prove to a jury that the attorney provided representation. The correspondence between the attorney and the plaintiff may be provided as proof, as well as the litigation documents or papers authored by the attorney.