Litigating Fingerprint Evidence: Ensuring a Statistical Foundation Swofford, H.J. Chair, Friction Ridge Subcommittee, OSAC Chief, Latent Print Branch, U.S. Army Criminal Investigation Laboratory Fordham University School of Law, June 2018

Calls for Reform National Research Council. 2009. Strengthening Forensic Science in the United States: A Path Forward. Washington, DC: The National Academies Press. https://doi.org/10.17226/12589 Expert Working Group on Human Factors in Latent Print Analysis (U.S.), National Institute of Justice (U.S.), & National Institute of Standards and Technology (U.S.). (2012). Latent print examination and human factors: Improving the practice through a systems approach : the report of the Expert Working Group on Human Factors in Latent Print Analysis. Washington, D.C.: National Institute of Standards and Technology. REPORT TO THE PRESIDENT, Forensic Science in Criminal Courts: Ensuring Scientific Validity of Feature-Comparison Methods, Executive Office of the President, President’s Council of Advisors on Science and Technology. 2016 American Academy for the Advancement of Science (AAAS), Forensic Science Assessments: A Quality and Gap Analysis, Latent Fingerprint Examination, AAAS, 2017.

Image license free for public share and use from clipart The Issue Detect Measure Evaluate ? Image license free for public share and use from clipart

Image license free for public share and use from clipart The Objective Detect Measure Evaluate Image license free for public share and use from clipart

Current State of the Practice Step 1: Analyze the impression to visually assess the quality and quantity of information Fingerprint image(s) from NIST SD 27; Image license free for public share and use from Clipart

Current State of the Practice Step 2: Compare and visually assess the similarity between the impressions and form an opinion regarding the significance of those measurements Fingerprint image(s) from NIST SD 27; Image license free for public share and use from Clipart

Image license free for public share and use from clipart Current State of the Practice Problems: No measurements taken No documentation No standards for interpretation Image license free for public share and use from clipart

Image license free for public share and use from Clipart Bridging the Gap & Promoting Reform How? A B Image license free for public share and use from Clipart

Image license free for public share and use from clipart Future State of the Science Basic tenets of science: DOCUMENT the details utilized MEASURE the attributes of those details EVALUATE the significance of those measurements REPORT conclusions which are substantiated by the data Image license free for public share and use from clipart

Future State of the Science Step 1: Measure the quality of the impression & Evaluate the significance of those measurements Fingerprint image(s) from NIST SD 27; Image license free for public share and use from Clipart

Future State of the Science Step 2: Compare & measure the similarity between the impressions and evaluate the significance of those measurements using empirical datasets Image license free for public share and use from clipart; Fingerprint Image(s) from NIST SD 27 FRStat Logo depicted above is the property of the U.S. Government

Future State of the Science Measure the similarity between the impressions and evaluate the significance of those measurements using empirical datasets

Future State of the Science RESULTS OF EXAMINATION The latent print on Exhibit 1 and the standards bearing the name XXXX have corresponding ridge detail. The probability of observing this amount of correspondence is approximately 96,000 times greater when impressions are made by the same source rather than by different sources. TECHNICAL NOTE The statistical calculations in this report were generated using FRStat software. Results equal to or greater than 10 indicate a positive association between two impressions. Correspondence is measured with respect to the spatial relationships and angles of the annotated ridge details and reflected as a similarity statistic. Uncertainty of measurement is calculated using an iterative random sampling scheme for the annotated details. The reported result is the lower bound of the 99% confidence interval. FRStat is not designed to evaluate all aspects of the impressions, such as pattern type, feature type, intervening ridge counts, and other details considered by an examiner; thus, the reported results indicate a conservative estimate for the statistical strength of an association between two impressions.

Future State of the Science “Association” threshold tied to empirically tested data

Image license free for public share and use from Clipart Bridging the Gap & Promoting Reform That sounds great, but not all laboratories have those capabilities . . . Can they implement these capabilities? Image license free for public share and use from Clipart

Image license free for public share and use from clipart Bridging the Gap & Promoting Reform YES!!! Laboratories ARE ABLE to access latent print quality software* Laboratories ARE ABLE to access statistical interpretation software* Laboratories ARE ABLE to ensure reported conclusions are grounded by available facts or data * Available to most US government entities Image license free for public share and use from clipart

Bridging the Gap & Promoting Reform

Bridging the Gap & Promoting Reform YOU can help strengthen the foundation of fingerprint examination – hold the expert and laboratory accountable to demonstrate: WHAT was observed HOW it was measured WHY it is “significant” WHERE is the data to substantiate the conclusion

Henry Swofford Chair, Friction Ridge Subcommittee, OSAC Chief, Latent Print Branch, USACIL Henry.J.Swofford.civ@mail.mil (404) 469-5611