What Are The 4 Types Of Evidence?

    In Brief:

  • Demonstrative evidence refers to evidence like x-rays, audio-recordings, videos, and maps that give a physical representation of the crime.

  • Real evidence refers to evidence that was present or used at the scene of the crime like a murder weapon or blood-stained clothing.

  • Testimonial evidence refers to evidence given by a witness as to what they saw or heard that pertains to the trial.

  • Documentary evidence refers to evidence in the form of documents like a deed, newspaper, diary, or contract.

Evidence means everything in a court case. When there is enough evidence to support one side of a court case, that side typically wins. There are four types of evidence that the court system accepts when it comes to deciding a person or organization’s guilt. They include demonstrative, testimonial, documentary, and real evidence. A judge, prosecutor, or defense attorney may also deem evidence be suppressed or immaterial for several crucial reasons in order for a trial to remain fair and impartial. Learn more about evidence and how it is used during a trial below.

The 4 Types Of Evidence:

Demonstrative Evidence

Demonstrative evidence refers to evidence in the form of a representation of an object. Items like x-rays, maps, voice-recordings, videos, and simulations are all considered demonstrative evidence. As such, demonstrative evidence provides a physical illustration of a fact. This form of evidence is an extremely useful type of evidence due to the simple fact that most people retain visual information at a higher rate than audio information. According to one study, demonstrative evidence increases the rate of information retention by between 10 and 80 percent. 

Demonstrative evidence is often used by experts to support and strengthen their claims. A handwriting expert will use images of a letter to prove its validity, while an audio expert may be asked to play an audio recording to determine whether it has been tampered with.

Photos of a crime scene also give jurors an optimal picture of the crime scene including how the bodies are strewn across the scene, blood spatter, and damage to the scene which may entail signs of a struggle. Demonstrative evidence should always be used as an aid for the jury to better understand the case. A court may not allow demonstrative evidence if it does not serve this function.

Real Evidence

Real evidence refers to any piece of evidence that was present or used at the scene of a crime. Things like a gun, knife, blunt-object, bloodied clothing, DNA, and fingerprints is considered real evidence. In order to be admitted at a trial, real evidence must be authentic, relevant, and material. An attorney must establish these prerequisites in a process called laying the foundation where he or she calls a witness to the stand who establishes the evidence’s chain of custody.

Real evidence can quite literally be the “smoking gun” when it comes to determining guilt. If the murder weapon is found with the suspect’s DNA on it, a jury may be very likely to reach a guilty verdict. If DNA found on a rape victim is different than that of the suspect, the jury may be more likely to reach a not-guilty verdict. 

Testimonial Evidence

Testimonial evidence is considered the simplest type of evidence. Testimonial evidence does not require another piece of evidence to support it like other types of evidence. When a witness describes something they saw or heard that pertains to the case at hand, this is considered testimonial evidence.

Testimonial evidence is considered more subjective than physical because it relies on the witness’s memory which may or may not be accurate. A prosecutor may call a police officer to the stand in order to confirm that the defendant is the person who indeed committed the crime in question. Witnesses must be deemed competent before they can provide their testimony. 

A competent witness must:

  • Take an oath to tell the truth
  • Be knowledgeable about what they are testifying about
  • Have a recollection about what they saw or heard
  • Be able to communicate what they saw or heard

Documentary Evidence 

Documentary evidence can be considered real evidence. For instance, if a trial surrounds whether there has been a breach of contract, the actual contract is the documentary evidence. Documents that can be admitted as evidence include newspaper articles, contacts, letters, diaries, and much more. Documentary evidence must be authentic and relevant to the court case in order to be admitted as evidence.

Admissibility Of Evidence

Evidence must be more than just relevant and authentic. All types of evidence must be determined to have a probative value as well – the ability to prove or disprove facts. This probative value must not be outweighed by shock value or prejudicial value.

As such, evidence must be determined to play an important role in determining guilt. In a breach of contract trial, evidence that it was raining on the day the contract was signed – whether physical or testimonial – is considered immaterial because it does offer anything to the actual case. Quite simply, evidence must offer some benefit to the juror’s understanding of the case. Evidence is the bedrock of all trials and must be treated as such.