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Evidence is important in both and Civil law cases. For the purposes of the law relating to evidence, we classify evidence in a number of different ways.

• by directness;
• by meta;
• by originality

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In addition, it is necessary to consider whether evidence is admissible or not (see: Admissibility Of Evidence).

Classification by directness Evidence is direct if, were it believed, it would immediately establish the fact in question. For example, if a police officer saw a person break a car window and steal the radio this is direct evidence. Note that whether evidence is credible is not an issue here; directness is not predicated on credibility, but its closeness to the fact.

If evidence is not direct, then it is circumstantial. For example, if the police officer sees a suspect running away from a car with a broken window, and carrying a car radio, then this is circumstantial.

Classification by meta Evidence may be oral (usually given by witnesses, see: Examination of witnesses, Competence and compellability of witnesses), documentary or 'real' (e.g., objects).

Classification by originality

This issue is much more subtle that it first appears. Evidence is either original, or it is Hearsay. If a police officer testifies that he saw X breaking into a car, this is original evidence of the fact concerning X. If he testifies that Y told him that he (Y) saw X breaking into a car, then this is hearsay against X. It is, of course, direct evidence of the speech by Y -- but this is a different matter. The distinction is important, because hearsay evidence is not usually admitted in criminal cases. A notable exception, of course, is a confession by the accused.