The opinion
ADAMS, Judge,
concurring in part and dissenting in part:
I fully concur with the majority opinion in all respects except the decision to vacate the trial court’s apportionment of liability and remand for an apportionment based upon additional medical evidence. On the issue of proper medical evidence upon which to base apportionment, there is a critical difference between the record in this ease and the record in Lummus Construction v. Vancourt, 838 P.2d 43 (Okla.App.1992).
In Lummus, the trial court did not apportion although the claimant admitted a preexisting injury from previous employment. The employer had offered medical expert evidence which recommended apportioning the claimant’s impairment based on the ratio of the length of time working for the particular employer to the number of years working in the industry. The expert testified that this recommendation was based on his sense of “fairness” and professed no basis for his conclusion in scientific or medical principles.
Lummus noted that such medical evidence, i.e., evidence admittedly based on the expert’s sense of “fairness” and not on any scientific or medical principle, was “arbitrary and incompetent,” and that the trial court did not err in failing to follow that apportionment theory. At least in the opinion of this writer, Lumm/us does not stand for the proposition that apportionment may not be based on relative length of employment if such an apportionment is based upon proper medical evidence.
The record here is far different. The only medical evidence on apportionment is the parties’ stipulation that if Dr. H (Claimant’s medical expert) testified he would attribute ninety-five percent of Claimant’s impairment to one employer and five percent to the other. The trial court’s order followed that testimony. Dr. H was never questioned about the basis for this opinion. Unlike the record in Lummus, this record does not indicate that Dr. H’s opinion was not based on some scientific or medical principle. 1
We must treat this record as if Dr. H appeared and testified as the parties stipulated. Under 12 O.S.1991 § 2705, Dr. H was not required to disclose the underlying data and facts upon which his opinion was based unless the trial court required otherwise or he was questioned on cross-examination. Neither occurred here, and I do not believe his testimony on this issue should be rejected as a basis for the trial court’s order simply because the majority presumes he had no scientific or medical basis for that testimony.
I would sustain the trial court’s order in its entirety because it is supported by competent evidence. I respectfully dissent to that portion of the majority opinion which does otherwise.
. The majority suggests that Dr. H's testimony was based on the number of months worked because Claimant's counsel indicated that would be the basis when he offered the stipulation. However, the transcript does not indicate that stipulation was accepted. Rather, after some off-the-record discussion, the parties stipulated that Dr. H would testify to ■ a 95/5 apportionment. Even if Counsel's explanation is considered, there is no indication that Dr. H did not have a valid scientific or medical basis for choosing such a method.