In order for negligence to be proven a Claimant (usually the patient) must show that the doctor owed a duty of care to the patient, that the doctor was negligent in his or her management, and also that the patient suffered harm as a result. The Claimant has to succeed on both liability and causation to obtain compensation: Liability to show that the doctor or nurse must have been found to have acted in a manner that no other similar professional would have done. Causation that harm has resulted which would not otherwise have occurred (on the balance of probability, ie the action of the doctor or nurse was more than 50% likely to have caused the harm). The Claimant's loss is then assessed in terms of quantum (loss of current and future earnings, reduced quality of life, mental anguish) and the recompense is money - nothing more and nothing less. The rules by which civil cases are conducted are the Civil Procedure Rules (CPRs) and doctors giving evidence as expert witnesses have to follow Part 35 of those rules in the submission of medical evidence.