Much of legal malpractice law is based on some form of negligence. To be deemed negligent in legal malpractice a certain set of criteria needs to be met. The doctrine that was formed to define legal malpractice is res ipsa loquitur and under it there are four chief criteria that must be met. However, res ipsa loquitur is a broad term that is applied general to common law with respect to legal malpractice.
In some states legal malpractice laws are very strict while in other state legal malpractice laws are much looser. This difference allows for more cases to be filed in states with loose legal malpractice laws as their res ipsa loquitur is more broadly defined, or easier put allows for more actions to be counted. Conversely in states where legal malpractice laws are strict the res ipsa loquitur doctrine is narrowly defined allowing for specific offenses to be counted, in effect protecting the lawyer against at times what can be upset clients if they lose a case.
Both strict and lose interpretations of res ipsa loquitur have central elements in common law that are then tightened or loosed. So all states play of the same playbook but they interpret the plays differently. Four main elements need to be present in order for a legal malpractice lawsuit to be rock solid. The first is quite simple in a basic normal setting the event that occur to prompt a response against the lawyer would not have occurred if there was not some form of negligence.
The second would be that someone had to be negligent for it to happen the way it did. Both legal and medical malpractice share much in common with res ipsa loquitur doctrine the situations just manifest in different ways. The last two are opposites of each other, the first is that the defendant caused the injury and the second is that the plaintiff in no way helped to cause the injury. Clear examples of legal malpractice and medical malpractice can be shown in this example. When a doctor leaves behind a scalpel it fits all the res ipsa loquitur requirements; it in fact shows gross negligence that no other reasonable doctor would commit.
When a lawyer forgets to submit a filing with the court in turn derailing the case for his or her client it is an example of an action that no other lawyer would commit causing harm to their client, and once again fitting the res ipsa loquitur doctrinal requirements. Depending on the state the doctrine will hold to all parties involved. That is to say if one lawyer makes a negligent mistake or a doctor makes a mistake and in both cases they are part of a team, then the whole team is held accountable.
Even under res ipsa loquitur doctrine the burden of proof with still fall on the plaintiff. However, it may be clearer to surmise negligence in legal malpractice because usually a lawyer needs to do something that can be readily documented as a mistake. However, in both legal and medical malpractice a poor performance by a doctor or lawyer is not ground for malpractice.