Motions To Exclude Or Limit Evidence Of Retrograde Extrapolation

“The generally accepted rate of burn-off is about one beer per hour, based on the “average man.” However, the “average man,” like the “average family” with 2.4 children, doesn’t exist; the only rates which have relevance are the rates of the person on trial. Absorption and elimination rates are affected by a myriad of factors.” Using an oversimplified model, assume that there are 20 variable which contribute to the rate of absorption and that each of these variables has only 2 values. The mathematical formula for this model is 2 n where n=20. “Extrapolation back from the BAC at the time of testing to the BAC at the time of driving is an endeavor fraught with the danger of inappropriately bamboozling the jury into thinking that such an extrapolation can be anything close to accurate. The information which is usually available to the expert doing the extrapolation is woefully inadequate to make even an educated guess about a range of possible BACs.” GUESSING BACKWARDS

Factors: 1. Weight 2. Gender* 3. Physical Condition 4. Metabolic Rate 5. Time of Day 6. When Something Was Eaten 7. What Was Eaten 8. How Much Was Eaten 9. Time Drinking Started 10. What Was Consumed 11. How Much Was Consumed 12. Drinking Pattern 13. Altitude 14. Point of Woman’s Menstrual Cycle 15. Emotional State 16. Whether Defendant Is An Alcoholic 17. Inherited or developed tolerances 18. Whether Medication Was Taken* 19. What Medication Was Take 20. When Medication was Taken If you assume there are only 5 values per variable ( ), the total number of possible combination is 3,814,697,265,629. We can extrapolate in regards to which way each known factor, in isolation, will affect absorption and burn-off, but prediction becomes more complicated each time another factor is added to the equation. Very quickly, accurate extrapolation becomes impossible.

Mata v State of Texas (2001) 13 S.W.3 rd 1 (2001) Evidence of Retrograde Extrapolation is inadmissible unless shown to be relevant and reliable. Judges are gatekeepers to weed out JUNK SCIENCE. Scientific community is divided over validity of retrograde extrapolation. (Kelly/Frye Standard) In order for it to have any relevance or reliability, expert must have evidence of at least the length of time of drinking, the time of last drink and the person’s weight. Since there are so many variables (At least 20) The more factors known to the expert, the more likely that the application of this theory will be reliable.