In E.I. du Pont de Nemours & Co. v. Robinson, 923 S.W.2d 549, 556 (Tex. 1995), the Texas Supreme Court espoused six factors that it felt would be helpful in determining whether expert testimony is reliable: (1) the extent to which the theory underlying the expert's testimony has been tested; (2) the extent to which the technique relies upon the subjective interpretation of the expert; (3) whether the theory has been subjected to peer review and/or publication; (4) the technique's potential rate of error; (5) whether the underlying theory or technique has been generally accepted as valid by the relevant scientific community; (6) the non-judicial uses which have been made of the theory. See Robinson, 923 S.W.2d at 556-57 Expert testimony commonly is in the form of an opinion. See Ford Motor Co. v. Aguiniga, 9 S.W.3d 252, 262 (Tex. App.--San Antonio 1999, pet. filed). Whether the opinion rises to the level of admissible evidence is determined by the rules of evidence. See generally TEX. R. EVID. 702; Aguiniga, 9 S.W.3d at 262. Rule 702 requires that an expert be qualified "by knowledge, skill, experience, training, or education," and that his testimony assist the trier of fact in understanding the evidence or determining a fact in issue. TEX. R. EVID. 702; see also Merrell Dow Pharms., Inc. v. Havner, 953 S.W.2d 706, 712 (Tex. 1997), cert. denied, 523 U.S. 1119, 118 S. Ct. 1799, 140 L. Ed. 2d 939 (1998); Lincoln Property Co. v. Deshazo, 4 S.W.3d 55, 58 (Tex. App.--Fort Worth 1999, pet. denied). Another requirement is that the testimony be relevant and reliable. See Gammill v. Jack Williams Chevrolet, Inc., 972 S.W.2d 713, 728 (Tex. 1998); Robinson, 923 S.W.2d at 556; Aguiniga, 9 S.W.3d at 262; DeShazo, 4 S.W.3d at 58-59 (explaining that courts should not determine whether the expert's conclusion is correct, but rather whether the analysis used to reach it is reliable). Determining the admissibility of expert testimony within the scope of Rule 702 often requires courts to view proffered evidence from scientific fields such as medicine, physics, electronics, chemicals, or engineering. See DeShazo, 4 S.W.3d at 59. Rule 702 not only applies to scientific and technical matters in their traditional senses; it applies equally to witnesses with specialized knowledge or experience and allows them to determine ultimate issues of fact. See id.