Locard’s Exchange Principle and the Daubert Test
Locard’s Exchange Principle is based on the precept that when people interact within an environment, they always leave traces of their activities. This is the basic principle of forensic science. In the digital and physical world, Locard’s Exchange Principle applies in that if people attempt to steal, remove, add, alter, or delete electronic data, they will leave electronic traces of their activities. Computer forensic examiners must have the skills to be able to detect this trace evidence so it can be used as admissible evidence in legal proceedings.
The Daubert test is used to determine if a tool that is used to gather forensic evidence is reliable. The test is composed of the following four questions to determine reliability of a data gathering tool:
- Has the tool been tested?
- Is there a known error rate for the tool?
- Has the tool been peer reviewed?
- Is the tool accepted within the relevant scientific community?
Examiners who testify as expert witnesses are required to testify on the reliability and accuracy of the tools they use to gather electronic forensic evidence. The court uses the Daubert test to determine if evidence collected using the tool will be admitted as evidence.