The Basic Rule
Rule 702 – Testimony By Experts
(a) If scientific, technical or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion, or otherwise, if all of the following apply:
(1) The testimony is based upon sufficient facts or data.