by Roger Koppl
I gave a webcast yesterday on “How to Improve Forensic Science.” Online questioners challenged me on a point that I now recognize to be underappreciated: The “ACE+V methodology” of fingerprint examination lets you shop your verifications. Let me explain.
Fingerprint examinations are performed using the “ACE+V methodology.” The acronym stands for Analysis, Comparison, Evaluation, and Verification. The system requires “verification” of any “individualization.” (An “individualization” is just their word for a match.) The official guidelines say “all individualizations shall be verified.” They permit, but do not require blind verification. In practice, most fingerprints are subject to non-blind verification. (One survey of 42 labs found only one lab, the FBI lab, conducting blind verifications and that in only about 5% of the cases.) Typically, then, we have non-blind verifications, which are provided by colleagues in the same facility and requested only when a match is thought to exist. Many people have seen that this is not much of a check against error. There have nevertheless been cases of examiners shopping their verifications and the official guidelines provide at best inadequate discouragement of the practice. Here are the two examples I know of.
A Seminole County fingerprint scandal erupted in Spring 2007 when latent print examiner Tara Williamson issued a memo accusing her co-worker Donna Birks of misbehavior and incompetence. One of her specific charges regarded shopping verifications. Birks could not get verification for a particular print from two persons she approached in the lab. “The print was then sent to a retired [fingerprint] examiner [from the same office] who one year earlier medically retired early and had admittedly lost his eye for latent prints. This examiner should not have been deemed ‘competent’ and no allow (sic) to verify the print for such reasons (see SWGFAST Quality Assurance Guidelines for Latent Print Examiners. Page 5. 4.2.4).” (The underling was in the original memo.) Notice that the problem was seeking verification from someone who was not competent. The problem was not shopping the verification!
The second example comes from an official report on the case of Brandon Mayfield, whom the FBI mistakenly identified as the source of a print left at the scene of the Madrid train bombing. On page 115, the report says:
“The [FBI’s Latent Print Unit] Quality Assurance Manual provided that if the second examiner reached a different conclusion, the matter “must be referred to the supervisor and/or the Unit Chief for resolution.” No formal statistics regarding the frequency of this occurrence have been maintained by the LPU, but LPU witnesses interviewed by the OIG stated that a refused verification was as an extremely unusual event. One option available to the supervisor was to select another verifier if the first verifier declined to confirm the identification. In that instance, there was no policy requiring that the first verifier’s disagreement be documented in the case file.”
The report does not suggest that there was verification shopping in the Mayfield case. But it does reveal that it was considered just fine to shop your verifications. The official guidelines say, “When examiners have conflicting conclusions, a quality review shall be conducted.” It does not say, however, that the failed verification must be included in the case file. “A quality review shall be documented and include” several items, the first of which is a “review of case documentation.” Apparently, such documentation is not meant for the case file, where no “review of case documentation” would be required.
The logic of verification shopping perfectly fits the argument of Feigenbaum, Susan and David M. Levy. 1996. “The Technical Obsolescence of Scientific Fraud,” Rationality and Society, 8: 261-276. The examiner who can shop his or her verifications has a powerful tool exclude competing views and thus protect an epistemic monopoly on interpretation of the evidence.