FINAL by: OSAC Program Office; Version 2, January 13, 2020 1

OSAC RESEARCH NEEDS ASSESSMENT FORM

Title of research need: Probability of Randomly Acquired Characteristics

Describe

the need:

Investigate the statistical probabilities of randomly acquired characteristics (RACs) 

occurring in the same position and orientation on different outsoles and/or tires. 

Quantitative results should include data originating from both high-quality exemplars and 

crime-scene impressions.

Keyword(s): RACs, probability, frequency, chance co-occurrence, position, shape, geometry

Submitting subcommittee(s): Footwear & Tire Date Approved: October 24, 2022

Background Information:

1. Does this research need address a gap(s) in a current or planned standard? (ex.: Field identification system 

for on scene opioid detection and confirmation)

2. Are you aware of any ongoing research that may address this research need that has not yet been published 

(e.g., research presented in conference proceedings, studies that you or a colleague have participated in but 

have yet to be published)?

3. Key bibliographic references relating to this research need: (ex.: Toll, L., Standifer, K. M., Massotte, D., eds. 

(2019). Current Topics in Opioid Research. Lausanne: Frontiers Media SA. doi: 10.3389/978-2-88963-180-3)

• J. A. Speir, N. Richetelli, M. Fagert, M. Hite, and W. J. Bodziak. (2016) “Quantifying randomly acquired 

characteristics on outsoles in terms of shape and position,” Forensic Science International, Vol. 266, pp. 399–411.

• Cassidy, M. (1995). Footwear Identification. Published by Lightning Powder Company, Inc. in cooperation with the 

Royal Canadian Mounted Police. ISBN 0‐9622305‐8-8, pp. 1-176. 

• N. Richetelli, W.J. Bodziak, J.A. Speir. (2019) ““Empirically observed and predicted estimates of chance 

association: Estimating the chance association of randomly acquired characteristics in footwear comparisons,” 

Forensic Science International, Vol. 302, 109833. doi.org/10.1016/j.forsciint.2019.05.049

• Stone, R. (2006). Footwear Examinations: Mathematical Probabilities of Theoretical Individual Characteristics. 

Journal of Forensic Identification. Vol. 56, No. 4. pp. 577-599. 

• Wilson, H. (2012). Comparison of the Individual Characteristics in the Outsoles of Thirty-Nine Pairs of Adidas 

Supernova Classic Shoes. Journal of Forensic Identification. Vol. 62, No. 3, pp. 194-203. 

4. Review the annual operational/research needs published by the National Institute of Justice (NIJ) at 

https://nij.ojp.gov/topics/articles/forensic-science-research-and-development-technology-working-groupoperational#latest? Is your research need identified by NIJ?

No.
FINAL by: OSAC Program Office; Version 2, January 13, 2020 2

5. In what ways would the research results improve current laboratory capabilities?

The day-to‐day operations of the laboratory are not expected to change as a function of this research. However, the 

reporting structure, possible strength of conclusions, and analyst training may change over time to incorporate 

research findings. Downstream digital and web‐based applications for data analysis (of crime scene samples) are also 

foreseeable, but these would be long‐term outcomes beyond the scope of this initiative.

6. In what ways would the research results improve understanding of the scientific basis for the 

subcommittee(s)?

The basis of source identification in forensic footwear and tire comparison is a function of the perceived limits in 

chance co-occurrence of RACs. However, the discrimination potential ascribed to a single or combination of RACs is 

believed to vary as a function of RAC size, shape, quality, clarity and complexity. This research will serve to evaluate 

the leading hypothesis and quantitatively define the certainty to which a RAC (or RACs) can support source 

identification.

7. In what ways would the research results improve services to the criminal justice system?

The potential for chance co-occurrence of randomly acquired characteristics directly impacts the degree of 

confidence to which a conclusion of source identification can be made. If this confidence can be described 

quantitatively, and/or illustrated using research examples, the trier of fact will have additional information and 

illustrations on which to evaluate the weight of evidence offered in criminal proceedings that include footwear and 

tire impression evidence.

8. Status assessment (I, II, III, or IV): II

Major gap in 

current 

knowledge

Minor gap in 

current 

knowledge

No or limited

current research is 

being conducted I III

Existing current 

research is being 

conducted II IV

This research need has been identified by one or more subcommittees of OSAC and is being provided as an 

informational resource to the community.