Define: Best Evidence

A rule of evidence that demands that the original of any document, photograph or recording be used as evidence at trial, rather than a copy. A copy will be allowed into evidence only if the original is unavailable.

The best evidence rule allows for the “original” evidence to be produced to prove what the document states. The reason this rule was implemented was that copies could have errors. For example, if someone copied a letter mistakes could have been made in the transcription or details could have been obscured by the handwriting. Copies of pictures could also have the colours changed or be manipulated.

Over the years the best evidence rule has lost significance, however, since copies of the originals are no longer produced by hand but can be reproduced in a very high-quality form, and the copies are generally as clear and good as the originals. Electronic communications have also created even more difficult because it can be impossible to tell if a file is an original or a copy, although it is possible to collect data such as when the file was generated and when it was altered. In this situation, the court may apply the best evidence rule on a case by case basis.

A copy of a document or testimony by a witness would be “secondary evidence. Secondary evidence cannot be introduced under the best evidence rule unless the best evidence cannot be obtained.

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This glossary post was last updated: 29th March, 2024.