If you watch any of the television shows that center around law and justice, chances are you have come across cases where the trial became a battleground for “expert witnesses.” Often one side would claim one thing and provide supporting evidence while the other side would claim the exact opposite and provide equally valid supporting evidence.

The reality is there are instances when the facts of a case are open to interpretation, even when it gets down to numbers and figures. Expert witnesses are qualified to give opinions that may be considered facts because they have the training and knowledge to deliver such opinions from a professional perspective. And yet, there may be more than one conclusion to be arrived at given a set of circumstances.

In a DUI (driving under the influence) case, for example, the prosecutor will routinely send test results to a Forensic Toxicologist employed by the Department of Justice to interpret as evidence for trial that is also prepared to get on the stand and explain what the results mean to the jury in terms they can understand as laypeople. However, the expert witness may not know all the facts that may impact on the test results, such as the machine used was defective, the samples had been tainted, or the defendant has a medical condition that resulted in a false positive.

The defendant in such cases has the right to challenge the prosecutor’s expert witness but it has to be substantiated by an expert witness as well to objectively provide an alternative explanation for the results that may exonerate the defendant or at least ameliorate the offense. An experienced criminal defense lawyer would know if an expert witness is appropriate under the circumstances (they can be expensive) and if so, what kind of expert witness may be needed to rebut the claims of the prosecution. Furthermore, defense lawyers often have expert witnesses for all types of cases in their roster that they know are qualified, credible, and reliable for the best possible shot of helping a defendant beat the charges.