Most evidence at a trial involves testimony on subjects with which we are all familiar. Examples are testifying on the type of shoes a person was wearing when that person slipped and fell in an icy parking lot or whether the driver of a car smelled of alcohol at the time of a car accident.
However, a trial judge will at times need specialized evidence to assist in the determination of a case. This specialized evidence is called opinion evidence and often involves the issue of negligence of a professional person. Such an allegation requires proving the accepted standard in the industry for the delivery of professional services. This is done by calling an expert in the field to give an opinion on what the standard is and whether the professional on trial has met or fallen below that standard. If the professional has fallen below the standard, negligence is proven.
For example, in a medical malpractice lawsuit, a doctor will be called by each of the plaintiff and defendant to prove the accepted standard in the industry. This may involve a “battle of the experts” debating, for example, whether the standard of a doctor practising in a rural community is different from the standard of a doctor practising in a city like Toronto. Another example is a contractor who builds a house but the roof collapses due to the snow load in the winter. Was the roof properly built? Should engineered trusses have been used? These are questions to be answered by experts.
Whether your case is in the Small Claims Court or in the Superior Court of Justice, always keep in mind that you cannot prove or defeat an allegation of professional negligence without the assistance of expert evidence.