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 in the form of an opinion or otherwise, if the proponent demonstrates to the court that it is more likely than not that:
§ 2702.Testimony By Experts
Chapter 40: Oklahoma Evidence Code · Last amended September 1, 2025 · Last verified August 3, 2026
In one sentenceLets a qualified expert testify by opinion when specialized knowledge will help the trier of fact, if the proponent shows it's more likely than not that the testimony will help, rests on sufficient facts or data, follows reliable principles and methods, and reliably applies them to the case's facts.
Full Text of § 2702
1. The expert's scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue;
2. The testimony is based upon sufficient facts or data;
3. The testimony is the product of reliable principles and methods; and
4. The expert's opinion reflects a reliable application of the principles and methods to the facts of the case.
Amendment History
Amended by Laws 2025, c. 311,s. 9, eff. 9/1/2025. Added by Laws 1978, SB 276, c. 285, § 702, eff. 10/1/1978; Amended by Laws 2009, HB 1603, c. 228, §18, eff. 11/1/2009.
Note
Laws 2009, c. 228, § 18 was held unconstitutional by the Oklahoma Supreme Court in the case of Douglas v. Cox Retirement Properties, Inc., 2013 OK 37, 302 P.2d 789 (Okla. 2013) and repealed by Laws 2013, 1st Ex.Sess., c. 15, § 1.
Plain-English Summary
Section 2702 sets the gate expert testimony has to clear. An expert, qualified by knowledge, skill, experience, training, or education, can testify in opinion form or otherwise when scientific, technical, or other specialized knowledge will help the jury understand the evidence or decide a fact in issue. The proponent carries the burden: the court must find it more likely than not that the expert's knowledge will help, that the testimony rests on sufficient facts or data, that it's the product of reliable principles and methods, and that the expert reliably applied those principles and methods to the facts of the case.
That "more likely than not" language, added by a 2025 amendment, tracks the same standard added to the Federal Rules of Evidence effective December 2023 -- both hold the proponent to a preponderance-of-the-evidence burden across all four requirements. A compiler's note explains that an earlier, 2009 version of this section was declared unconstitutional by the Oklahoma Supreme Court and later repealed, so the four-part test now in force comes from the 2025 rewrite of the reliability standard, not that invalidated language.
Frequently Asked Questions
What does a party have to prove before an expert can testify?
The four things listed in paragraphs 1 through 4 -- that the expert's knowledge will help the trier of fact, sufficient facts or data, reliable principles and methods, and reliable application to the case -- each shown to be more likely than not.
Does the expert's opinion have to be based on actual facts or data?
Yes, paragraph 2 requires that the testimony be based upon sufficient facts or data.
What happened to the 2009 version of this rule?
The Oklahoma Supreme Court held it unconstitutional and it was later repealed; the current four-part reliability standard traces to a 2025 amendment.
Is Oklahoma's expert-testimony standard the same as the federal one?
Closely aligned -- the four numbered requirements and the "more likely than not" burden match the version of Federal Rule of Evidence 702 that took effect in December 2023.
What kinds of expertise qualify someone as an expert under this section?
Knowledge, skill, experience, training, or education, per the section's opening paragraph.
Source & verification. Section text is reproduced verbatim from
Title 12 of the Oklahoma Statutes, enacted by the Oklahoma Legislature.
Last verified August 3, 2026.
· Official source
Also known as: oklahoma expert witness standard12 O.S. § 2702FRE 702 oklahoma daubert standardmore likely than not expert testimony oklahoma