Expert witnesses: Who are they and what do they do?

On Behalf of | Aug 9, 2023 | Criminal Law

If you are charged with a crime, witnesses can play a powerful role in the outcome of your case. While some of these witnesses are people who saw or heard an event take place, other witnesses are experts who have specific knowledge on a particular issue. 

Expert witnesses can testify for the prosecution or the defence, so it is crucial to understand who they are and what they do.

Common types of experts

Experts are people with special knowledge, skills or training in a particular area they use to provide informed opinions. They also can explain complex issues in a way that lay people in the courts can better understand. 

The type of expert that testifies in a case depends on the nature of the allegations and any evidence available. In the context of criminal charges, however, some examples of expert witnesses can include experts in:

  • Police procedure
  • Forensics
  • Mental health
  • Accounting

There are many other types of experts who may be part of a criminal case, but this list represents some of the more common individuals you might encounter if you are facing criminal charges.

Are the experts always right?

Experts provide an opinion in court based on their knowledge and training, as well as examinations and tests they may conduct. As such, their testimony can be powerful in proving or disproving a specific point, but experts are not unimpeachable.

For instance, imagine the prosecution in your case uses an expert witness to provide an opinion on DNA collected at the scene. In that case, part of your defence could include calling a different expert to disprove, contradict or devalue the statements the other witness made.

However, it is crucial to note that under Canadian laws, expert witnesses have a duty to be impartial, independent and objective. As such, selecting experts and determining how best to use them can require sophisticated legal knowledge and familiarity with criminal proceedings. 

Defending against criminal charges is vital in protecting your freedom and future, but it is not easy. That said, resources and tools, like expert witnesses, can help bolster your defence to avoid wrongful convictions and unfair penalties.