8. The opinion rule and the presentation of expert evidence
Titles in the Core Text series take the reader straight to the heart of the subject, providing focused, concise, and reliable guides for students at all levels. The ‘opinion rule’ is one of the major exclusionary rules of the law of evidence. This chapter discusses the following: the general rule excluding evidence of opinion; four exceptions to the opinion rule born of necessity; the principal exception to the opinion rule: expert opinion; the presentation of DNA evidence; and the use of the Bayes’ theorem and instructing the jury in mathematical probabilities.