Double Loop Podcast

Eric Ray and Glenn Langenburg catch up on a mix bag of topics in the first episode of 2022. Emails on the new conclusion proposal, setups for photography with transmitted light, and the main topic on "qualitative statements". ANAB accreditation requires agencies to include a statistic or a qualitative statement when reporting an association. What does that mean? What qualifies as quantitative? Is...

In this episode, the guys talk about Thanksgiving: Eric’s amazing food preparation and Glenn’s travel to Canada to teach. Eric also gives a plug for Kasey Wertheim’s fingerprint book library that is up for auction. In the main segment, they discuss two of the new ASB proposed standards out for public comment. Specifically, they examine differences with these documents and those proposed by OSAC, n...

Eric Ray and Glenn Langenburg discuss the recent paper on Blind Proficiency Testing from the Houston Forensic Science Center: "Latent print quality in blind proficiency testing: Using quality metrics to examine laboratory performance" by Brett O. Gardner, Maddisen Neuman, and Sharon Kelley. The paper describes the results of over two years of blind proficiency testing in the latent print unit. No...

The long awaited/dreaded return of the “Dad Joke Intro”! In this episode, Todd Weller (firearms expert) returns to the show to talk to Eric and Glenn about the article on inconclusive decisions by Itiel Dror and Nicholas Scurich [(Mis)use of scientific measurements in forensic science; Forensic Science International, 2020; 2:333-338]. Todd gives his views on how the article mischaracterizes the er...

Return with Glenn and Eric to the IAI Conference in Nashville, TN. The guys are joined by Josh Connelly, Kurt Aebersold, JP Rodriguez, and Claudine Carter Pereira. New accuracy studies, open field research, and stat talk. And we're already looking forward to next year's conference in Nebraska!

Glenn Langenburg and Eric Ray review the 2020 article from Itiel Dror and Nicholas Scurich. "(Mis)use of scientific measurements in forensic science" was published in Forensic Science International: Synergy. The article criticizes published accuracy studies in the latent print and firearms disciplines and suggests an alternative method for handling inconclusive decisions and calculating an error r...

Glenn Langenburg and Eric Ray discuss how to testify in court after an error occurs. Examiners nervous about upcoming testimony can find tips whether you made the error or a co-worker made an error and whether it was an erroneous identification or an erroneous exclusion. The court and juries do not expect us to be perfect, and we should claim to be. It's important to be able to discuss the Quality...

In this episode, the guys return for Round 2 with Dr. Heidi Eldridge and Prof. Christophe Champod. This time, they discuss the second paper arising from the palm print black box study (discussed in DLP Episode #234). The focus in this episode is “Mind-set – How bias leads to errors in friction ridge comparisons” by Eldridge, de Donno, and Champod in Forensic Science Int’l 318 (2021). This paper ex...

Glenn Langenburg and Eric Ray are joined by Todd Weller to discuss the firearms/toolmarks discipline. Todd was involved in the NY firearms case from Episode 227 and shares his experiences there. The guys then talk through accuracy studies for firearms examiners and similarities and differences between firearms and fingerprints. Lots to cover in an extra-long episode.

In this episode, Eric and Glenn are joined by Dr. Heidi Eldridge and Prof, Christophe Champod, the authors of "Testing the accuracy and reliability of palmar friction ridge comparisons - A black box study". The guests describe the design, the aims, and the results of the study. We get into discussions about the meaning and usefulness of error rate statistics and confidence intervals from performan...

Glenn Langenburg and Eric Ray finally get back on track with a review of a recent article on GYRO markings. "Evaluating the Accuracy and Weight of Confidence in Examiner Minutiae Annotations" was written by Jeremy John and Henry Swofford and published in the JFI. The study measured whether examiners placed minutiae markers on true minutiae using Green, Yellow, and Red markers. It then compared the...

Glenn Langenburg and Eric Ray review the newest article from Austin Hicklin, Bradford Ulery, Madeline Ausdemore, and JoAnn Buscaglia. Why do latent fingerprint examiners differ in their conclusions? reviews data from the Black Box, White Box, and Eye Tracking papers, summarizes trends through all of that research, and recommends changes for the fingerprint field.

After some Halloween talk, Eric and Glenn discuss this episode’s research article: “The Utility of Expanded Conclusion Scales During Latent Print Examinations” by Carter, Vogelsand, Vanderkolk, and Busey in J Forensic Sciences (online, 2020). This study examines the results of 27 experts who completed 30 comparisons under a 3-point SWGAST scale versus 30 comparisons under a 5-point OSAC scale. The...

In this Halloween episode, Eric and Glenn discuss a new paper published by Koehler and Liu titled “Fingerprint error rate on close non-matches” (Journal of Forensic Sciences, Sept. 2020). The paper raises a lot of discussion between the guys regarding close non-matches, inconclusives, training, and testimony. They each have a different take on some of the key issues in the paper, but in the end id...

Glenn Langenburg and Eric Ray pay special tribute this week to a giant in the fingerprint world, Bob Garrett. With the passing of Bob and a few other close friends and colleagues, Glenn and Eric want to look back at the contributions of Bob Garrett in particular. In his single year as president of the IAI, he was instrumental in responding to the NAS Report, addressing the McKie controversy, and m...

In this episode, Glenn and Eric discuss a recent case Glenn was involved in: a knuckle-crease case. The case had a Daubert hearing in addition to trial testimony for jurors. The guys discuss if non-friction ridge skin associations would meet the Daubert factors. If you were preparing for such a hearing, what research and testing would you need to demonstrate expertise of the expert, or demonstrate...

Glenn Langenburg and Eric Ray review a recent court decision on firearms testimony. NY v Ross was a recent Frye case where the testimony of firearms examiners was restricted to only class characteristics. Was this a fair decision? Did the judge raise good points? How does this case relate to latent print testimony and latent print accuracy studies? Join us for an hour of fun talk as we dive deep i...

Glenn Langenburg and Eric Ray were recently asked which latent print books they recommend the most. This episode they talk through the absolute creme de la creme of fingerprint tomes. New books, old books, green books, blue books. Whether you're developing or comparing ridges, we've got a list of what you need to read. Also make sure to join us Wed nights at 8pm EDT for Virtual Happy Hour at https...

This week, the guys review and share their reactions to the documentary “The Most Dangerous Animal of All” (produced by Campfire Productions and available now on F/X and Hulu). This is a story about Gary Stewart who believes his father, Earl Van Best, Jr. was the infamous Zodiac Killer in San Francisco in the 1960s/1970s. The series reveals who Gary is and his obsession with the Zodiac. Then it sh...

Glenn Langenburg and Eric Ray take a break from normal interviews and research reviews to host a laid-back happy hour discussion on how things have been different in the past few months in forensic crime labs. Carey Hall, Becca Coutant, and Josh Connelly join our discussion that meanders from discussions on web-based training, remote testimony, recent changes to in lab life, and TV recommendations...

Eric and Glenn wrap up their “activity level series” by discussing two articles (Girod, et al. 2016; and Hinners, et al. 2020) which propose determination of aging of latent fingerprint residue. The techniques use instrumental techniques to identify breakdown products of various fatty components in latent print residue, and use these results to classify whether a latent print is a couple of days o...

In the final and third part of the series on the Massachusetts drug scandals and Netflix documentary, we interview Luke Ryan, the defense attorney featured in the documentary and who represented several of the clients affected by the scandal. Luke described how and why he fought to uncover the truth that was being swept under the rug by the Attorney General’s office. We also discussed a number of...

Eric and Glenn finish out their discussion of the new Netflix documentary “How to Fix a Drug Scandal” (2020). In this episode we switch our focus on the dry-labbing of drug tests by Annie Dookhan, and how long it took for those tests and convictions from those test to finally get tossed. The episode concludes with the story of Luke Ryan and his crusade to finally find the evidence that clearly dem...

In the wake of COVID-19 and so many of us staying at home, we decided as an April Fools’ Episode to make a list of movies that we enjoy and feature an aspect of forensic science. Eric and Glenn run down our top 10 movies (with two “so bad, they’re good” recommendations) and a few honorable mentions for you to consider while deciding what movies or shows to binge. We also alert listeners at the end...

In the first of two episodes, Glenn and Eric discuss Netflix’s “How to Fix a Drug Scandal” (2020), covering the actions and consequences of two Massachusetts drug chemists. In this episode, they mostly focus on the Sonja Farak aspect, who was a drug chemist, addicted to drugs and stealing drugs from her standards cabinet and evidence. The guys discuss the issue of ‘random drug screenings’ of crime...