[2] The Court in Frye held that expert testimony must be based on scientific methods that are sufficiently established and accepted.
[3] The court wrote: Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define.
Somewhere in this twilight zone the evidential force of the principle must be recognized, and while the courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs.
States still following Frye include: California, Illinois, Minnesota, New York, Pennsylvania, and Washington.
Novel techniques, placed under the scrutiny of this standard, forced courts to examine papers, books and judicial precedents on the subject at hand to make determinations as to the reliability and "general acceptance."