(concurring in part and dissenting in part).
{53} I agree with the speedy trial analysis in Judge Fry’s majority opinion, but I disagree with the evidentiary discussion. I have no quarrel with the discussion of prior cases dealing with application of the Daubert/Alberico standard in general. However, I do think that the opinion ultimately goes too far in finding a strict dichotomy between assessing the validity and reliability of scientific techniques versus deficiencies in the actual application of a technique or principle. As the opinion notes, courts are to consider the method used to generate offered scientific evidence. Thus, I disagree that New Mexico does not require a proponent of evidence to show “ ‘proper application of the technique on the occasion in question.’ ” Majority Opinion, ¶27 (quoting Mata, 46 S.W.3d at 908).
{54} There can be instances where application or performance of a valid and reliable technique is so flawed that the results are not trustworthy enough to be admissible. For example, an accident reconstruction opinion as to whether a party had sufficient time to avoid a collision would likely not be admissible if the expert refused to include a factor for driver perception and reaction time in the mathematical calculation or if the expert assumed a coefficient of friction that the scientific literature indicated was unrealistically high or low in the circumstances. This case presents a similar problem. I think the method used by the State’s expert is so flawed that it cannot be deemed sufficiently reliable to be admitted.
{55} There is no need here to re-canvass the literature or case law concerning retrograde extrapolation. It is enough to acknowledge that the technique is recognized by the scientific community as “valid”; that is, a reasonably accurate — though not precise — calculation of BAC at a given time pretest can be achieved when the technique is correctly applied with sufficiently reliable data. The universally recognized difficulty with proper application of the technique is assuring that the various factors which can affect the final value dramatically are appropriately assessed, quantified and applied. Our opinion in Day discusses these factors at length. Day may be too categorical in its apparent requirement that all factors should be dealt with explicitly in all cases, but that does not erase the point that retrograde extrapolation in an uncontrolled environment is devilishly difficult.
{56} The State’s witness evaded all of these difficulties through the use of assumption, negating any need to figure out how the considerations described in Day affected his work. He avoided the need to calculate an actual rate of elimination by using a range of values rather than calculating Defendant’s specific rate. He could assume a range of values for the rate of elimination in this case because the State did not care about proving a specific BAC; all it wanted to do was show some not insignificant level. In a ease which does not require proof of a specific BAC, this approach might be acceptable since it appears that once a person is post-absorptive and post-peak, the rate of elimination — whatever it is — is reasonably constant for a given person. This aspect of the case clearly swayed the district court to admit the testimony.
{57} What destroys the trustworthiness of the approach here is the assumption that Defendant was post-absorptive when the accident occurred. I see no basis in the record for the assumption. Accepting the assumption turns the extrapolation into a simple arithmetic operation. No expertise is required to extrapolate if you assume all variables away. Given his unrealistic and unsupported assumptions, the State’s expert’s approach provides no more than theoretically possible values untethered from the actual case at hand. The fact that taking the usual factors into account yields values ranging from less than .04 to over .12 at the time of the accident tells me that the State’s approach is not valid and should have been excluded.
{58} Proper assessment of method in this case would not have made the district court a “third expert.” Rather, it would have been the essence of gatekeeping.