In this case the material fact was the concentration of alcohol in the appellant's body at the time he was arrested while driving, which was 3:05 a.m. ⁽¹⁾ About two hours later the defendant gave two samples of his breath, a few minutes apart, for testing. ⁽²⁾ The testing instrument reported his alcohol concentration as being 0.196 in the first sample and 0.193 in the second. ⁽³⁾ George McDougall was asked what the range of alcohol concentration of "a male" would have been when he was arrested if he had stopped drinking at least two hours earlier. ⁽⁴⁾ McDougall answered:

I believe that the high side would have been somewhere around a .04 higher than that, which would be a 0.23 and then his body would have eliminated the equivalent of two drinks during those two hours. On the low side, his body could have absorbed two or three drinks and as much as a .04 or a .06, reached a peak and either maintained that level or decreased a little bit until the time of arrest, which would make him, I guess, at the low side of a .13. So I would say somewhere between a .13 and a .23. ⁽⁵⁾

He explained that "he would need to know his body weight" to know how much alcohol was in the male's system when he was tested. He said he could conceive that the male could have had an alcohol concentration below 0.10 at the time he was stopped if "just before he was stopped he chug-a-lugged a lot of hard liquor, hard alcohol." To say how much alcohol, he would need to know the male's body weight. ⁽⁶⁾

On cross-examination he agreed that, because he lacked several pieces of information, the breath test in this case did not tell the defendant's alcohol level at the time he was driving. ⁽⁷⁾ He did not observe the defendant's driving or his drinking or whether he had had anything to eat, and he did not know the defendant's weight. ⁽⁸⁾ He agreed that he did not know when "the peak of the [defendant's] blood alcohol absorption/elimination occurred," that he could give a better answer if he knew that fact, and that his opinion was "based upon some assumptions about absorption and elimination rates," which varied among individuals. ⁽⁹⁾ He also admitted that his opinion was based on "a normal drinking pattern," and that he did not know the defendant's drinking pattern. ⁽¹⁰⁾

Q. So that range is based upon an assumption that doesn't apply to Mr. Mata, is that correct?

A. It may not, yes, sir.

Q. So that range that we have there may not be his range?

A. That is possible, yes.

Q. This is a hypothetical based upon your person, the average person?

A. Yes. ⁽¹¹⁾

All of the testimony that I have mentioned was given to the jury. It also should be noted that, outside the presence of the jury when the district court was considering the admissibility of McDougall's testimony, the defense counsel asked similar questions, concluding with these:

Q. So your hypothetical has to deal with an average person or a reasonable person and not specifically with my client?

A. With a reasonable possibility of drinking, yes.

Q. What you consider are the reasonable possibilities of drinking?

A. Exactly. ⁽¹²⁾

I have set forth these details because, in my view, they determine the outcome of this case, in which the witness's qualifications are not challenged and in which his testimony clearly referred to a hypothetical or average person. I do not think the trial court abused its discretion in finding that such general testimony would "assist the trier of fact to understand the evidence or to determine a fact in issue," Tex. R. Evid. 702. The jury was given general information about alcohol concentration's varying over time as alcohol is introduced, absorbed, metabolized, and eliminated; about the usual speed with which this may happen in an average person; and about the fact that these processes vary among individuals and in response to the behaviors that accompany the drinking.

The case might be different if the witness had expressed an opinion about the defendant's blood alcohol, or if his qualifications had been challenged. Of course I express no view about such questions.

I would affirm the judgments below.

En banc.

Delivered June 6, 2001.

Publish.

1. See Testimony of Kenneth Wayne Thompson, 3 Reporter's Record (hereinafter "RR") at 146, 189.

2. See Testimony of Arnold Santos, 3 RR192, 195, 196.

3. Testimony of George Allen McDougal, Jr., 233. Alcohol concentration is "the number of grams of ethyl alcohol that are found in 210 liters of the vapor being analyzed." Id. at 232.

4. "A male blows a .193 two hours after they were stopped, two hours after we know at least that they had stopped drinking two hours prior. Can you give us a range as to what his alcohol concentration would have been at the time he was stopped?" Id. at 257.

5. Ibid.

6. Ibid.

7. Id. at 264.

8. Ibid.

9. Id. at 270.

10. Id. at 295.

11. Id. at 296.

12. Id. at 252.