ABSTRACT
For centuries, the Anglo-American law did not distinguish one type of expert testimony from another. On the surface, a uniform standard governed the admission of the testimony of all qualied experts. e evidence had to be relevant and not too prejudicial or timeconsuming, and it had to deal with matters not comprehensible to ordinary jurors without the assistance of an expert. A pristine statement of the position is that
Although this relevance-helpfulness requirement applies to all expert testimony, scientic and nonscientic alike, it need not have the same impact on all types of expert testimony. Scientic evidence tends to be time-consuming or dicult to understand. Courts fear that it comes cloaked in an aura of infallibility that leads jurors to give it more credence than it deserves. Consequently, ad hoc balancing of probative value and its counterweights can operate to exclude scientic evidence, especially if the science is not well established. Nevertheless, in practice, the relevance-helpfulness standard promotes “a generally laissezfaire approach to the admissibility of expert evidence” (Law Commission 2011, 16).
