§ 1.02 PROOF AT TRIAL

• Jurisdiction: United States

§ 1.02. PROOF AT TRIAL

There are some basic issues that any system of proof needs to confront. We, of course, will focus on the adversarial system used in this country.²

[A] Procedural Aspects

Burdens of proof. A fundamental issue involves the allocation of burdens of proof: the burden of persuasion and the burden of production.³ What if the evidence adduced at trial is insufficiently persuasive under some defined standard? Who should lose the case?

Moreover, in defining the burden of persuasion, do we want to favor one party over another by placing a thumb on the scales of justice, so to speak? There are two types of errors that can be made in a criminal case: (1) false positives — convicting the innocent, and (2) false negatives — acquitting the guilty. As a policy matter, we want to avoid the former more than the latter, and thus, we use a high burden of persuasion in criminal cases, i.e., proof beyond a reasonable doubt. The same policy issue is absent in civil litigation. Thus, a preponderance of evidence standard is used because the system is expensive, and we do not want a tie at the end of a one week, one month, or one year trial. Special procedural rules, called presumptions, assist parties in meeting their burdens of proof.⁴

Order of proof. Trials also need "housekeeping" rules. In offering evidence, who should go first? Who goes second, and does the first party have a right to offer rebuttal evidence? The order of trial is: (1) plaintiff (prosecution) case-in-chief, (2) defense case-in-chief, (3) plaintiff rebuttal, and (4) defense surrebuttal.⁵ The party with the burden of production goes first because if that party fails to meet that burden, the trial can end with a directed verdict right then. In examining witnesses, the same issues arise: who examines first, second, and should there be any further examination? The answer: (1) direct examination, (2) cross-examination, (3) redirect examination, and (4) recross examination.⁶

Judge and jury functions. The system also needs to allocate responsibility between the judge and jury.⁷ The jury decides the "facts," which includes the credibility of witnesses. The judge decides the admissibility of evidence (once an objection is raised) and runs the trial.⁸

[B] Communicating Information to the Jury

Testimonial proof. In the common law system, proof typically comes in the form of witness testimony. The first issue is who should be considered a competent witness.⁹ In other words, should a person be kept off the witness stand (disqualified) because that person is too young or suffers from a mental disability.

Another issue is the credibility of witnesses, i.e., their worthiness of belief.¹⁰ Some witnesses lie, but more often witnesses are inaccurate for other reasons, such as poor eyesight, unconscious bias, or an inadequate opportunity to observe. Efforts to diminish a witness's credibility fall under the rubric of "impeachment." In addition, some rules, such as the firsthand knowledge and hearsay rules, are designed to ensure that the most reliable evidence is presented at trial.

Documentary evidence. In addition to testimony, proof may...