Which of the following is a permitted source of an expert's knowledge at trial?

The correct answer is that an expert may rely on facts or data presented to them that were not entered into evidence, as long as those facts or data are of a type that experts in the field would typically rely upon in forming their opinions. This principle recognizes that experts often draw on a wide range of information in their specialized areas, which may not be presented directly as evidence in court. Such reliance is acceptable when the information is generally accepted in the relevant field as reliable and vital for their expert analysis.

This approach is crucial because it allows experts to provide informed opinions based on their training and experience, which may include a variety of sources, including data from literature, past studies, or industry standards, so long as it meets the criteria of general acceptance in their field. It helps ensure that juries receive comprehensive insights without cluttering the trial with unnecessary details of every piece of information considered by the expert.