Systems Thinking and DNA Mixtures: Dynamic Models, Optimization, Validation and Inference

This workshop introduces systems thinking with demonstrations on applying a systems approach to forensic DNA mixture interpretation, optimization and validation. Topics to be covered include validation of the DNA interpretation pipeline containing probabilistic genotyping software, focusing on current and forthcoming OSAC/ASB and SWGDAM mixture interpretation validation and verification standards and guidelines. Also included will be a review of published literature with discussions on the foundational validity of mixture interpretation and the impact of laboratory accreditation. Future directions for improving front end processing steps will also be discussed.

Learning Outcomes:

By the end of the workshop attendees will:

1. Be cognizant of why a systems thinking approach to validation will positively impact mixture interpretation results and probabilistic genotyping outcomes
2. Have explored the entire post-extraction laboratory system (quantification to LR computation) using a dynamic model parameterized by experimental data. We shall demonstrate that the entire process can be evaluated in a cost- and time-efficient manner by surveying common laboratory parameters such as cycle number, injection time, and analytical thresholds
3. Have explored methods to quantify the impact of their processing decisions on the likelihood ratio and its distribution
4. Understand the differences and relationships between sensitivity, resolution, analytical thresholds, and other relevant analytical figures
5. Recognize the differences and relationships between accreditation, validation, optimization and verification within the laboratory’s DNA testing and interpretation processes
6. Be exposed to a comprehensive review of mixture interpretation publications and findings from the NIST DNA Mixture Review that should be published in July 2018
7. Be better informed on the standards for mixture interpretation, protocol development, and probabilistic genotyping validation and recognize the limits of data and mixture interpretation

Intended Audience:

DNA Technical Leaders, Laboratory Directors, DNA analysts, QA/QC managers, attorneys, academicians, consultants and aspiring DNA analysts.
Pre-requisites include: Experience with forensic DNA profiling techniques and STR data interpretation. Minimal working knowledge or experience with genotyping software would be helpful but is not required.

Agenda: