What is Required in DUI Cases (2019)
Here you will find:
- The defintion of “Metrological Tracability.”
- What does it require must be proven?
- How flawed traceability can artificially increase a BAC.
A measurement is only as good as its calibration. Traceability is how, the person who wants you to rely on the measurment, proves its reliability.
Measuring An Unknown
The warning labels provided by crime labs are not only inadequate, the are misleading.
An important limitation, that is often overlooked, are the problems associated with measuring an unknown amount. Measuring an unknown value is the process attempting to hit an unknown target.
When you want to measure something of an unknown value, your measurement is only as good as, your measuring process.
Every measurement contains uncertainty. A measurement is not complete unless that uncertainty has been quantified.
The true value which every measurement attempts to obtain is unknowable. This is because “closeness of agreement” requires two known values.
Think of ruler with markings that represent it’s 12 inches long. However, it’s actually only 10 inches long.
- Each and every measurement will be incorrect – every time.
- Each and every measurement will be precise – every time.
When the a ruler is smaller than its 12 inch markings, the result is an artificially higher value (i.e. 10 inches is now represented to be twelve 12 inches).
Furthermore, each an every measurement made with this ruler will provide an artificially larger measurement. Thus, a defective ruler can simultaneously be both precise and incorrect…every time it’s used to measure something.
At the same time, to the human eye, the measurement looks correct. This is because we lack context and the necessary scientific nuts and bolts to know better. We didn’t know to ask the right questions:
- How was the ruler calibrated?
Was a traceability reference standard used?
Did the person making the ruler show their work?
In sum, getting two test results numerically close, does not answer the question relevant question: can we rely on the results to determine innocence or guilt?
Put another way, without the necessary scientific nuts and bolts in hand, it’s impossible to know what questions (and their answers) actually matter. The right questions can uncover ideas, thoughts and possibilities we have never considered.