Evidence: Scientific Evidence & Expert Witnesses

Expert witnesses are witnesses that are called to testify based on their specialized knowledge, not necessarily their direct knowledge of the events and issues at trial.  As result expert witnesses are allowed to answer different questions than lay witnesses, but are also subject to additional requirements.  To be qualified as an expert witness, the proferring attorney must demonstrate why the witness is an expert and that the methods they rely upon are generally accepted in their professional community.  Once this is satisfied, expert witnesses may offer opinions and theories on the issues at trial, as opposed to lay witnesses that are generally restrained from such speculation.