Who determines the qualifications of an expert witness in a trial?

The qualifications of an expert witness in a trial are determined by the trial judge. This is based on the judge's role in ensuring that the testimony presented is both relevant and reliable according to legal standards. When an expert is proposed to testify, the judge evaluates their credentials, experience, and the methods they used to arrive at their conclusions in order to assess whether the expert's testimony meets the criteria established under rules of evidence.

The judge's decision is guided by criteria such as the expert's qualifications in their field, their knowledge, skill, experience, training, or education, and whether their expertise will assist the jury in understanding the evidence or determining a fact in issue. This process is crucial because it protects the integrity of the trial by ensuring that only those who can provide credible and relevant expertise are allowed to influence the jury’s understanding of complex matters.

The other parties in the trial, such as the prosecution and defense attorneys, may propose or challenge the admissibility of an expert witness, but it ultimately falls to the judge to make the final determination about their qualifications. The jury does not have a role in evaluating expert qualifications as they are the fact-finders who rely on the evidence presented to them.