Physics and Pattern Evidence

Scientific Area Committee

Chair: Austin Hicklin, Noblis

AAFS — February 2017
Pattern SAC Leadership

• Officers

• Chair: R. Austin Hicklin, Noblis

• Vice Chair: Lesley Hammer, Hammer Forensics

• Executive Secretary: Thomas Busey, Indiana University, Bloomington

• Subcommittee Chairs:

• Bloodstain Pattern Analysis: Toby Wolson, Retired (Miami-Dade Police 

Department)

• Firearms and Toolmarks: Andy Smith, San Francisco Police Department Crime 

Lab

• Footwear and Tire: G. Matt Johnson, Orange County Crime Laboratory

• Forensic Document Examination: Rigo Vargas, Mississippi Crime Laboratory

• Friction Ridge: Melissa Gische, Federal Bureau of Investigation

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Pattern SAC Members and Liaisons

• Members

• David Baldwin, Special Technologies Laboratory, USDOE

• Ted Burkes, Federal Bureau of Investigation

• Paul Kish, Paul Erwin Kish Forensic Consultant & Associates

• Nicholas Petraco, John Jay College of Criminal Justice

• Hal Stern, University of California, Irvine

• David Stoney, Stoney Forensic, Inc.

• John Vanderkolk, Indiana State Police Laboratory Division

• Ex-Officio Members

• Liaison to Human Factors Committee: Rick Lempert, University of Michigan

• Liaison to Legal Resource Committee: David Kaye, Pennsylvania State School 

of Law

• Liaison to Quality Infrastructure Committee: Erin Henry, Oklahoma State 

Bureau of Investigation

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Pattern SAC: Role

• Provide direction and oversight for 5 subcommittees

• Firearms & Toolmarks

• Footwear and Tire

• Friction Ridge

• Questioned Documents

• Bloodstain Pattern Analysis

• Interface with the resource committees 

• Human Factors

• Legal Resource

• Quality Infrastructure

• (OSAC-wide Forensic Statistics Task Group)

• Communicate activities, progress, recommendations

• Review, facilitate public comment, and approve standards and 

guidelines

• Coordinate research priorities

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Pattern SAC : Purpose

• To foster the development of rigorous standards and guidelines 

within and across the pattern disciplines

• To assist in the adoption of these standards and guidelines

• To encourage enforcement of these standards and guidelines through 

accreditation, certification, and training

• To encourage evaluations to test and validate procedures

• To encourage research to improve the disciplines

• To enhance the rigor of these disciplines through transparent, 

accurate, and reliable processes

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Pattern SAC: Priorities

• Coordination across disciplines in these areas

• Current:

• Conclusions

• Terminology

• Future:

• Reporting

• Training/competency/certification/proficiency

• Accreditation

• Testimony

• Imaging

• Documentation

• Collection/Crime scene investigation

• Research/General discipline needs

• Validation

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Pattern SAC: Role of affiliates

• Standards and guidelines are developed by task groups (with 

oversight from the SACs and subcommittees)

• Task group participation is not limited to OSAC members: 

subcommittee chairs can name OSAC affiliates to task groups

• International participants can participate as affiliates

• Active participation as an affiliate is considered in new member 

selection

• If interested, contact the appropriate subcommittee chair

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Goals for standards and guidelines

• Standards and guidelines need to be practical: to be as rigorous as 

practical given current capabilities 

• BUT 

• OSAC also needs to recommend research to continually improve the 

disciplines in these areas

• Terminology and conclusions: consistent across disciplines

• Procedures: as quantitative and objective as practical 

• Documentation: complete and transparent

• Conclusions, Reporting and Testimony

• include all data on which conclusions are based

• distinguish data, conclusions, and opinions

• clearly state the limitations and caveats of conclusions

• clearly specify the bases of opinions

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Building on the work of the SWGs

• We want to make sure that OSAC does not sacrifice any of the benefits and 

successes of the SWGs

• Areas where OSAC can improve on SWGs:

• Formal standards 

• SWG standards were often informal (or were actually guidelines), not defined in a way that 

would meet the requirements of a standard from an SDO (Standards development 

organization)

• More powerful voice in making recommendations

• Better enforceability

• SWGs had no means of enforcing standards, no real authority 

• OSAC’s unified voice should have more authority in tying OSAC standards to training, 

accreditation, and certification

• Coordination among disciplines

• Broader basis for input and review

• Membership is broader by design (e.g. including academic researchers)

• OSAC includes statistical, quality, human factors, legal resources

• Input (task groups)

• Review (canvass process, SAC and FSSB approval)

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Current Progress

• Pattern SAC documents at AAFS Academy Standards Board:

• Scope of Expertise in Forensic Document Examination

• Guideline for the Articulation of the Decision-Making Process Leading to an 

Expert Opinion of Source Identification in Friction Ridge Examinations

• Many draft documents in progress in subcommittees

• Firearms/Toolmarks and Friction Ridge subcommittees replied to the 

Dec 2016 PCAST RFI

• Multi-discipline Standard for Source Conclusions under development

• 24 research needs (see next slide)

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Pattern SAC Research & Development Needs

Bloodstain Pattern Analysis:

• Behavior of Blood Outside the Body

• Bloodstain Pattern Classification 

• Examiner Reliability Study: Black and White Box 

Studies on Bloodstain Pattern Analysts 

• Interaction of Blood and Fabrics

Firearms & Toolmarks:

• Assessment of Examiners' Toolmark Categorization 

Accuracy

• Blind Verifications Needs Assessment

• Cognitive Bias: To What Extent Does It Affect Firearm 

and Toolmark Comparison Outcomes

• Effect of New Technology on Quantitative 

Consecutive Matching Striae ID Criteria

• Study to Assess the Accuracy and Reliability of 

Firearms and Toolmarks

Forensic Document Examination:

• Comparability and Complexity in Handwriting

• Hand Printing Complexity and Comparability

• National Database of Handwriting

• Validation of Conclusion Scale

Friction Ridge:

• ACE-V Bias

• Assessing the Sufficiency and Strength of Friction 

Ridge Features

• Close Non-Match Assessment

• Examiner Consistency During Friction Ridge Feature 

Mark-Up

• Friction Ridge Statistical Modeling

• Latent Fingerprint Image Quality Usage

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Footwear and Tire:

• Examiner Reliability Study: Black/White Box Study on Footwear and Tire Examiners

• National Footwear Database/Reference Collection

• Population Frequency of Class Characteristics: Footwear in the United States

• Probability of Randomly Acquired Characteristics

• Testing & Validation of 3D Imaging Technologies for Footwear & Tire Impressions Evidence
Comments or questions?

Austin Hicklin

hicklin@noblis.org

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