Expert witnesses are not the same as fact witnesses. Percipient witnesses and eyewitnesses are also called fact witnesses. These people will speak in court about relevant events that they personally experienced.
Fact witnesses have to make sure that what they’re saying is as accurate as possible. It’s best if they’re able to provide as many details as they can. They’re not supposed to provide their opinions related to any specialized subject. In order to do so, these individuals would have to be expert legal witnesses themselves.
People can become expert legal witnesses if they have certain levels of education or training, as well as relevant experience. Even then, professional witnesses have to make sure that their judgments are backed up by evidence and data, in addition to verified techniques and principles. These people cannot just rely on the authority that they already have.
Expert legal witnesses have to maintain a set of standards when providing their opinions on an important topic in court. An expert legal witness might provide fewer details than a fact witness in some cases because they’re drawing a conclusion based on the information that they have. However, all cases can certainly vary.