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"RETROGRADE EXTRAPOLATION"
is NOT reliable and should be
banned from Court rooms across the
United States (and beyond).
This past week "Retrograde Extrapolation" technique used by Prosecutors on Long Island to prove somebody's Blood Alcohol Concentration (BAC) Level at the time of driving has gotten some press...
What is "Retrograde Extrapolation" ?
It is a "faux" scientific calculation that is supposed to determine what a persons BAC level was at an earlier time based on the results of a chemical test that read BELOW 0.08%.
In other words, if you took a breath test and it read 0.06% BAC, a Prosecutor in New York could make an argument that based on this so-called scientific calculation, they could prove that your BAC at the time of driving was actually HIGHER than 0.08% (therefore, you could be found guilty of a DWI).
Why is "Retrograde Extrapolation" JUNK SCIENCE?
Because it makes very large assumptions in every single case. For starters, it assumes that every single human on earth eliminates alcohol from their system at a constant rate of 0.15% per hour.
Doctors and scientists have found very large ranges in people for alcohol elimination. Some alcoholics may process and eliminate alcohol at a much faster rate. The single rate used in this calculation fails to account for: gender, race, physical fitness, tolerance, food intake, digestion, age, strength of alcoholic beverage, trauma from an accident, etc, etc, etc,
It makes an ever bigger assumption when it assumes a point a time when a person's alcohol absorption "peaked."
When we drink alcohol there are two phases. The absorption phase and the elimination phase. During the absorption phase, we do not yet feel the effects of alcohol until it has fully been absorbed by our stomach and small intestine into our blood stream. Then it travels all over the body through our blood and we feel it in our head! (getting "buzzed")
Problem with RETROGRADE EXTRAPOLATION: there is no way to measure or know when a person has finished the Absorption phase! (PEAKED)
However, in order for a real, reliable calculation to work, we would have to know precisely when the alcohol absorption phase PEAKED and the body began to eliminate alcohol (assuming the rate is 0.15). Without that precise time, there would be NO WAY to ever know what somebody's BAC was by simply adding backwards.
That is why I have strong feelings about PSEUDO-SCIENCE being used in court rooms in front of a JURY. (this stuff is believable if you don't understand the science behind it!).
If a Jury is not comprised of chemists and biologists (or mathematicians), then it would be confusing and sound really easy to believe if an "expert" for the Government is saying that they did this calculation and they're SURE the Defendant was over 0.08% at the time of driving... And they will testify that it is based on SCIENCE.
Only it's NOT.
By Attorney Mike Cyr
607-229-5184
E: mike.ithacadwi@gmail.com
www.ithacadwi.com
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Copyright 2015
