Daubert standard

The Daubert Standard is a test used in US courts to decide if expert testimony is based on sound scientific theory. The standard says that when a witness is considered an 'expert'--someone with special knowledge about a topic--their opinion must meet four criteria to be considered valid in court. The four criteria are:

1. Is the theory or technique based on scientific knowledge?
2. Has the theory or technique been tested?
3. Has the theory or technique been published and reviewed by other experts?
4. Does the theory or technique have a high rate of error?

In plain language, this means that judges must make sure that the expert witnesses’ opinions that they allow into court make sense from a scientific point of view. In order for them to do this, the judge needs to make sure that the expert's theory or technique is based on scientific knowledge, has been tested and reviewed, and does not have a high error rate. If all these things are true, the judge can allow the expert testimony.