The source-of-duty rule discerns whether a duty stems from a contractual agreement or is derived from common law, affecting tort liability. For tort claims to proceed, there must be a duty that exists independently of any contract. In application, if a duty such as ensuring safety arises from common law and is breached, causing harm, this can ground a tort action even in the presence of a contract.
For example: A doctor bound by a contract to provide medical services to an athlete commits malpractice. Despite the contractual relationship, the doctor’s duty to provide competent care originates from common law, allowing for potential tort claims.