Lessons from State v. Herman et al.: When Software Errors, Human Errors, and Ignorance of Minimum Scientific Standards Provide the Basis for a Daubert Challenge in Understanding DUI Scientific Evidence (2014)

Abstract: From 2011-2014, four Arizona attorneys uncovered unexplained software errors on Scottsdale Crime Lab gas chromatograph (GC) #2003 including mislabeled vials, data transposition, and failure to acquire data.

A seventeen-day Daubert hearing ensued where the lab claimed ignorance regarding the scope of errors, never reported errors to ASCLD-LAB, and should've removed GC#2003 from service per the manufacturer. These problems, combined with a failure to follow ISO-17025 quality assurance requirements, permitted the trial court to rule GC#2003 results unreliable under 702(d). The chapter illustrates how headspace gas chromatography software errors, and a lab's failure to follow ISO-17025, provide a framework for challenges pursuant to Daubert.

How Mark DuBile Became Involved in this Book

Over the course of his career, Attorney Mark DuBile became more involved in national DUI defense organizations and developed a professional network with other prominent DUI attorneys across the country.

As the problems with the Scottsdale Crime Laboratory were exposed and challenged due to Mark’s efforts, a nationally recognized attorney invited Mark to author a chapter in his book to assist other attorneys who may face similar concerns.

Having been familiar with the publication, Mark was both honored and excited about the endeavor. Although this recognition was professionally gratifying, Mark felt that writing the chapter was an obligation he owed to his clients (past, present, and future), as well as to the general public.

Mark's opinion is that the scientific procedures and equipment used in DUI blood testing cases should be held to the same standards as a machine used to sterilize public drinking water or software used in producing results for dialysis patients. Science should not be compromised for cost or lack of training and certainly should not be held to a lesser standard for the sake of a criminal conviction.

Mark is thankful to be a part of the great team that exposed these errors and flaws; he and three other Arizona attorneys banded together to bring the case and all of them share the credit equally.

The Expert Factor: Effectively Attacking DUI Forensic Science Through Direct and Cross-Examination in Witness Preparation and Examination for DUI Proceedings (2015)


Because jury members are most often convinced of a defendant's guilt through the prosecution's presentation of the scientific evidence in a DUI case, it is important to be able to prepare and present a thorough defense that targets areas where scientific problems arise: in criminalist training, quality control, quality assurance, traceability, and ISO 17025 compliance.

A DUI defense attorney must be able to consult with an expert witness to review the evidence obtained from the State's scientist to discuss such factors as the methods and equipment used in obtaining blood results; what the lab's quality control measures mandate and whether they have been complied with; whether the lab is accredited by a higher agency and what the terms of accreditation are; whether those terms meet the requirements of ISO 17025; and how non-compliance in any of these areas can affect a defendant's case.

Further, the practitioner must be technically savvy regarding the equipment used to measure a defendant's sample for an alcohol concentration and aware of its inherent limitations, as well as recurring problems with the specific make and model. This consultation and subsequent preparation lays a strong foundation for expert testimony and criminalist cross-examination, which provides both counsel and client the best opportunity for success.

When does the State gain a strong foothold in a DUI trial?

It’s usually when a prosecutor says that science shows that a defendant’s blood alcohol concentration was over the legal limit. So how do you fight science? With better science and a more qualified scientist! Mark’s 2014 chapter informing other attorneys about the practical process of bringing a Daubert hearing was well received, and this chapter instructs attorneys and the public about the tools needed to dispute the State’s presentation of scientific evidence in a DUI case.

Through learning local and worldwide standards, gaining familiarity with the practices—and shortcomings—of crime labs in Arizona, and regularly consulting with scientists in the field, Mark has been able to speak to the State’s scientists in their own language and discover ways to strengthen the defenses in his clients’ cases.