It’s Just a Decimal Point: The Dirty Secret Behind Breathalyzers
October 25th, 2007 Posted in Breathalyzers, DUI/DWI, James Baxter
In 1990, the New Jersey courts declared that the science was settled, the debate was over: breath analysis is a reliable and accurate means by which to determine blood alcohol content (BAC). This proclamation is known as the “Downie decision.” The lead witness, who held the most sway in the court’s opinion, was Dr. Dubowski, a forensic scientist with a history of research experience dealing with Breathalyzers and alcohol breath analysis. A study he published in 1985 was considered the pre-eminent work in this field.
The Downie case revolved around the accuracy of breath analysis in terms of serving as a surrogate for actual BAC. One aspect would be of particular importance from the defendant’s perspective; how often does the alcohol breath analysis regimen overstate actual BAC? Dr. Dubowski testified that his research determined that in only 2.3 percent of the tests did the breath reading overstate the actual BAC. This was the first time this number was made publicly available; it had not been presented in his 1985 report.
Another witness in the Downie case, Dr. Gerald Simpson, a physical chemist also testified, and attempted to describe the variables that could render a Breathalyzer reading inaccurate. The court largely disregarded his testimony in favor of the assured endorsement of breath analysis offered by Dr. Dubowski. The court determined that the use of breath alcohol was scientifically valid for the purpose of determining BAC. Was that the end of the story? Not quite. After the Downie trial, Dr. Simpson obtained the actual data from Dr. Dubowski’s 1985 report. In applying the same analysis to the data that Dr. Dubowski used, Dr. Simpson discovered a major error. The incidences when breath analysis overstated actual BAC were not 2.3 percent of the tests, as Dr. Dubowski had testified to in the Downie case, but rather 23 percent of the tests – a wandering decimal point! Dr. Simpson then published his findings in a respected scientific journal. They were never rebutted and Dr. Dubowski remained silent on the subject.
Attorneys across the country have taken note of the breathalyzer’s failings. This has lead authorities to resort to more invasive measures, including letting officers perform blood draws with very little training. Recent research proves that measuring breath to determine actual BAC is a horrendously flawed concept. Errors can approach 50 percent! Still, even 15 years ago it was known and could be proven that in almost one quarter of Breathalyzer tests the readings were higher than the actual BAC. How many thousands of people had their lives turned upside down, suffered major financial losses, lost jobs, and had their reputations destroyed by a system that used junk science to push its agenda?