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Is Michigan Forensic Lab’s Lack of Blind Testing Cause for Concern?

Mar 14th, 2018 Criminal Evidence OWI Blood Testing Is Michigan Forensic Lab’s Lack of Blind Testing Cause for Concern?

There are about 30,000 drunk driving arrests in Michigan each year, and of these, about 1/3 of them involve blood tests for alcohol or controlled substances.  All of these blood tests are performed at the Michigan State Police forensic lab. And the blood samples all get to the lab the same way – they are sent by the police after an intoxicated driving arrest. This means everyone at the lab, from the lowest clerical staff, to the forensic scientists and lab supervisors, know that if blood is there, it’s because an (alleged) crime has been committed.  This seems to violate one of the most basic scientific protocols – blinded experiments.

A blinded-experiment is one in which information about the test is withheld to reduce or eliminate bias and subjective influence. Bias can be both unintentional or unconscious and for this reason blinded experiments do not suggest or infer dishonesty.  If dishonesty exists, however, blinded experiments are one way to ferret it out.  While blinded experiments are most often used in medical and psychological settings, blinded experiments also help to measure and increase the integrity of researchers and technicians, such as forensic analysists.

While forensic blood testing is not an “experiment” as such, inserting blinds into the system is one way that scientific credibility and objectivity can be maintained.  For this reason, the Houston Texas Forensic Science Center has begun sliding blind testing into the lab’s workload.  A recent article on the subject from poses this question:

Can we use blinds as a way of altering the behavior of the system in the direction that we want to?” said Peter Stout, the HFSC’s chief executive officer. “It’s an interesting psychosocial effect.

The article points out that do they receive and insert blood samples with .08 alcohol for testing but that other types of samples are often difficult to come by.  In Michigan, the forensic lab’s SOP (standard operating procedure) also includes a variety of calibrators and controls, including a whole blood sample.  While these are all good and do help, they are not a substitute for true blinds.

The above-cited article also indicates; the analysts processing the blinds appear to have accepted the testing in stride, Stout added. Instead of perceiving it as some intrusion into their workflow, it has instead only strengthened their testimony. This is especially true in toxicology cases, where the workers are often challenged in court, he added.

It gives them the ability to answer (attorneys’) questions appropriately,” said Stout. “They can say they never know whether they’re being tested.

Inserting blinds into the workload at Michigan’s forensic laboratory is one way to address possible bias, raise standards and reduce the possibility of false convictions.