Generally, legal malpractice occurs when an attorney, acting in their professional capacity as a lawyer is negligent. In this context, negligence is the failure of an attorney to exercise “reasonable care”—which means use a degree of skill that an ordinary member of the legal profession would use. In order to prevail in a suit for legal malpractice, the plaintiff must also prove that they probably would have won the underlying case but for their attorney’s negligence in handling their matter.
There are aspects of attorney malpractice claims that are distinct from other types of professional liability. Legal malpractice occurs only when an attorney makes a mistake that causes measurable damage to a person, which is usually but not always the attorney’s client. Not all mistakes by lawyers cause damage. Also, as long as the attorney’s judgment was based on an evaluation of the facts and law available to them, lawyers generally are not liable for errors in their professional judgment. For example, matters of legal strategy will not subject an attorney to legal malpractice liability as long as the lawyer's decision is a reasonable one. Otherwise, the decision could be considered legal malpractice.