burden of proof
: the responsibility of producing sufficient evidence in support of a fact or issue and favorably persuading the trier of fact (as a judge or jury) regarding that fact or issue the burden of proof is sometimes upon the defendant to show his incompetency —W. R. LaFave and A. W. Scott, Jr. — compare standard of proof
Note: The legal concept of the burden of proof encompasses both the burdens of production and persuasion. Burden of proof is often used to refer to one or the other. Burden of proof and burden of persuasion are also sometimes used to refer to the standard of proof.