1. Explain the differences between a lay witness and an expert witness.
    
2. Describe when a lay witness may give an opinion.
    
3. Explain the qualifications that must be satisfied in order for an individual to testify as an expert witness at a trial.
    
4. Explain why expert witnesses traditionally have not been permitted to testify about an “ultimate issue,” and how the Federal Rules of Evidence approach this issue.

SUMMARY: The Federal Rules of Evidence modified the common law prohibition on witnesses offering opinions. Opinion evidence by a lay witness must be based on the witness’s perception, must assist the jury, and must be nontechnical and straightforward.

Expert testimony can be of central importance in criminal prosecutions. Expert witnesses are witnesses who are qualified by “knowledge, skill, experience, training, or education” and may testify in the form of an opinion in their area of expertise. A trial court has the inherent right as recognized in Federal Rule 706 to call expert witnesses.