This type of evidence includes perception and memory, is subjective, and can be inaccurate. Almost all evidence must be sponsored by a witness who has sworn or solemnly affirmed to tell the truth. All persons are presumed to be qualified to serve as witnesses in trials and other legal proceedings, and all persons are also presumed to have a legal obligation to serve as witnesses if their testimony is sought. Witnesses are generally required to give their testimony in the form of statements regarding what they saw, heard, felt, tasted, or smelled, and they are generally forbidden to express opinion or draw conclusions. A person who is not testifying as an expert will be allowed to present an opinion as testimony if his opinion is both rationally based on his perception and helpful to an understanding of his testimony. Opinions of a competent layperson are specifically permitted by rule, statute, or case. In order to be accredited as an expert witness, academic qualifications and/or specific formal training is required and must be presented to the judge or jury. Qualification of an expert witness regards the witness's relative experience based on the complexity and subtlety of the subject matter. An expert witness is then permitted to state his opinions and draw conclusions within the scope of the issue at hand and his established field of expertise.
Chapter IX: Examination, Cross-Examination, and Impeachment
The Direct Examination, also called Examination-in-Chief, is the questioning of a witness by the party who called him/her in a trial, performed to elicit evidence in support of facts which will satisfy a required element of a party's claim or defense. Leading questions are usually prohibited, with the exception of the circumstance where a lawyer requests the judge to declare a witness to be a hostile witness. Cross-examination is the interrogation of the witness by the opposing counsel. In federal courts, most attorneys are not permitted to ask questions involving issues that were not raised during direct questioning, but most state courts do allow this type of questioning. The main purpose of cross-examination is to elicit favorable facts from the witness (es), or to impeach the testimony of the testifying witness to lessen the weight of unfavorable testimony. Redirect examination is the trial process where the party who offered the witness has a chance to explain or otherwise qualify any damaging testimony brought out by the opponent during cross-examination. Witness impeachment is the process of calling into question the credibility of an individual who is testifying in a trial. There are several methods of impeachment, including bias, inconsistent statement, character (specifically a community-recognized reputation for dishonesty or a prior criminal conviction for a crime involving dishonesty), competency, and contradiction.
Chapter X: Real, Demonstrative, and Scientific Evidence
Real evidence is also known as physical evidence and is any evidence introduced at a trial in the form of a material object that is intended to prove a fact in issue based on its demonstrable physical characteristics. Some examples are a written contract, the defective part or product, the murder weapon, trace evidence such as fingerprints or gunshot residue, and biological evidence such a blood, semen, or saliva. Admission of real evidence requires authentication, demonstration of relevance, and a showing that the object is in the "same or substantially the same condition" (Waltz and Park, 1998) now as it was on the relevant date. Authentication is achieved through witness statements or circumstantial evidence called the chain of custody. Demonstrative evidence is evidence in the form of a representation of an object, such as pictures, x-rays, diagrams, maps, graphs, simulations, and models. To be admissible, demonstrative evidence exhibit must fairly and accurately represent the real object at the relevant time. Scientific evidence is commonly presented by three separate types of witnesses: an educating witness, a reporting witness, and an interpreting witness. An educating witness, or teaching witness, teaches the jury or judge about the underlying scientific theory and instrument implementing theory. This witness is called to elicit an opinion that a theory is valid and the instruments involved are reliable. The reporting witness, usually the laboratory technician who personally conducted the test, is called after the teaching witness. This witness will describe both the test and its results. The interpreting witness, also called the evaluating witness, is used to complete the foundation of scientific evidence by stating the interpretive standard, applying the standard to the test result, and deriving a conclusion.
Chapter XI: Judicial Notice
Judicial notice is a rule in the law of evidence that allows a fact to be introduced into evidence if the truth of that fact is so notorious or well-known that it cannot be refuted. It is usually used for the simplest, most obvious common sense facts, such as which days of the week correspond to which calendar days. Federal Rules of Evidence allows judges to take judicial notice within two categories: generally known within the territorial jurisdiction of the trial court; and capable of accurate and ready determination by resort to sources whose accuracy cannot be reasonably questioned. Judicial notice may be permissive, in which the court may choose to accept judicial notice or reject the request and require the party to introduce evidence in support of the point, or mandatory in which the court must accept judicial notice. The effect of judicial notice is different in civil and criminal cases. In a civil action the court will instruct the jury that it must accept as conclusive any fact judicially noted. In a criminal case, the court will instruct the jury that it may, but is not required to, accept as conclusive any fact judicially noted.
Chapter XII: Burdens and Effect of Evidence
Proof can be defined as evidence that compels acceptance of fact or truth. The burden of proof refers to the burden of providing sufficient evidence to shift a conclusion from an oppositional opinion. Whoever does not carry the burden of proof carries the benefit of assumption, and the initiating party, which is the plantiff in a civil suit or the accusing agent - namely a county, city, or state - in a criminal case, normally carries the initial burden. This means that the bearer of the burden must present sufficient evidence to move the conclusion to their own opinion, which must be done in two ways - by establishing positive evidence and negating oppositional evidence. The concept of burden-shifting is the requirement that if one party produces evidence that tends to prove a point, the burden shifts to the other party to produce superior evidence to disprove that point. Different types of proceedings require parties to meet different burdens of proof, typically beyond a reasonable doubt, clear and convincing evidence, and preponderance of the evidence.
Chapter XIII: The Parol Evidence Rule
The Parol Evidence Rule is a substantive common law rule in contract cases that prevents a party from presenting extrinsic evidence that contradicts or adds to the written terms of the contract that appears to be whole. The supporting rationale is that since the parties have reduced their agreement to a single and final writing, the extrinsic evidence of past agreements or terms should not be considered when interpreting that writing as the parties ultimately decided to leave it out. The rule applies to parol - meaning oral - evidence as well as other extrinsic evidence regarding a contract. What this means is that in a contract dispute, such as one regarding the price of a vehicle, if the signed written contract states that the purchase price of the vehicle is $1,000 the contesting party cannot then testify that the seller offered to sell him the vehicle for $800. There are numerous exceptions to this rule, such as partially-integrated contracts or agreements with separate consideration, and extrinsic evidence can be admitted for a number of reasons, including to resolve an ambiguity, to disprove validity, to correct mistakes, and to show wrongful conduct such as misrepresentation, fraud, duress, unconscionability, or illegal purpose. The Parol Evidence Rule has a direct effect on consumers, for example in health club contracts, automobile sales contracts, and time share purchases, in that any spoken promises made to a consumer by a sales agent are generally not enforceable or admissible after a contract is signed by both parties.
Evidence law influences the information-gathering process. Laws affect every aspect of how information is obtained and presented through evidence in the trial process. There are laws that establish how much evidence is necessary to constitute a legal action and how much evidence is required to prove a case. The gathering of information and evidence must be focused on establishing the elements to a legal action and meeting the burden in proving that action at trial. There are rules that govern the admissibility of any evidence gathered. These rules also determine which evidence will not be admissible. For example, information will be excluded as evidence when it does not pertain…