Efficient Standard of Proof

One of the main functions of evidence law is to demonstrate the applicable standard of proof. In some kinds of evidence, it is not the case because fact finders make decisions according to the probative value of the evidence. In other pieces of evidence, there may be a need to find a standard. Lawyers trained in common law systems often enquire about the applicable standard of proof but in civil law countries and particularly Iranian law it depends on the discretion of judges and there are no clear rules. Instead, fact-finding standards are based on some general principles. In common-law systems, the standard of proof requires in ordinary civil cases the party who bears the burden of proof to establish by a "preponderance of the evidence". In some other civil cases "Clear and convincing" evidence is the main standard and in criminal cases "Beyond all reasonable doubt". By using normative considerations of efficiency, on the one hand, we may argue and propose that as the main principle, multiple standards are more efficient and will better align decision-making with fact-finding goals than using a unique standard and on the other hand, the preponderance of the evidence and clear and convincing evidence may be regarded as main standards.