Version 1 / Date of Issue: 10.29.15 / Issuing Authority: Forensic Science Standards Board (FSSB)

OSAC Research Needs Assessment Form

Title of research need: 

Keywords:

Submitting subcommittee(s): Date Approved: 

(If SAC review identifies additional subcommittees, add them to the box above.)

Background information:

1. Description of research need:

2. Key bibliographic references relating to this research need:

3a. In what ways would the research results improve current laboratory capabilities?

SEE ALSO ATTACHED ADDENDUM for additional details.

A problem in bloodstain pattern classification is that different bloodstain pattern analysts may give 

different classifications for the same pattern. Thus, more research is needed in order to minimize 

subjectivity in pattern classification. Currently, classification of a pattern results in the naming of a 

pattern using mechanism-based terminology. The mechanism by which a pattern was made, 

however, is part of the reconstruction process of a BPA scene. Thus, new research is needed in 

order to avoid mechanism-based terminology and to base the classification upon objective, physical

characteristics. 

- Arthur RM et al. A novel, element-based approach for the objective classification of bloodstain

patterns. For Sci Int 2015;257:220

- Saviano J. Articulating a concise scientific methodology for bloodstain pattern analysis J Forensic

Id 2005;55:461

- Gardner R. Defining a methodology for bloodstain pattern analysis. J Forensic Id 2006;56:549

This research will result in a unified framework for the classification of bloodstain patterns, based 

on physical characteristics of bloodstains. This unified framework will lead to a more objective and 

consistent method amongst bloodstain pattern analysts. It will decrease the error rate and increase 

the reliability of the method.

Bloodstain Pattern Classification

Pattern analysis, bloodstain pattern analysis, classification, blood

Bloodstain Pattern Analysis 1/5/17
Version 1 / Date of Issue: 10.29.15 / Issuing Authority: Forensic Science Standards Board (FSSB)

3b. In what ways would the research results improve understanding of the scientific basis for the 

subcommittee(s)? 

3c. In what ways would the research results improve services to the criminal justice system?

4. Status assessment (I, II, III, or 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.

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 will provide the field of bloodstain pattern analysts with a theoretical foundation for 

the classification of bloodstain patterns necessary for later studies in the accuracy and reliability of 

analysts. This research will lead to a better understanding of the decision-making process. It will 

provide guidance for the BPA subcommittee to revise current methods and to better reflect the 

current scientific state. A list of quantifiable, measurable and objective physical characteristics 

resulting from this research will help the subcommittee to describe the human pattern recognition 

process that has not been elucidated so far.

An objective method for pattern classification will lead to more reproducible and reliable outcomes 

amongst different bloodstain pattern analysts. This will result in a more justifiable framework 

leading to a cutting edge improvement to the criminal justice system.

I
Version 1 / Date of Issue: 10.29.15 / Issuing Authority: Forensic Science Standards Board (FSSB)

// Approval date:

(Approval is by majority vote of subcommittee. Once approved, forward to SAC.)

1. Does the SAC agree with the research need? Yes ⃝ No ⃝ 

2. Does the SAC agree with the status assessment? Yes ⃝ No ⃝

If no, what is the status assessment of the SAC:

Approval date:

(Approval is by majority vote of SAC. Once approved, forward to NIST for posting.)

SAC

Subcommittee

1/5/17
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ADDENDUM

Research questions regarding bloodstain pattern classification

OSAC Bloodstain Pattern Analysis Subcommittee

November 17, 2016

Introduction

This document serves as an addendum to the OSAC Research Needs Assessment Form entitled “Bloodstain 

Pattern Classification” approved by the Bloodstain Pattern Analysis Subcommittee on November 17, 2016. 

The BPA Subcommittee is of the opinion this addendum provides additional details not captured in said 

form.

What is the problem? 

1) Different people (of similar competence/experience) may give different classifications for the same 

pattern. 

Evidence: CTS proficiency tests/casework testimony

2) The inter and intra pattern variability is high: two impact patterns may exhibit as much variation as 

an impact pattern compared to an expiration pattern

Evidence: BPA course exercises/personal experimentation/casework examples

3) The descriptions of patterns are sometimes/often a description of the mechanism. The thought 

process during pattern classification is not well worked out: before classifying a pattern, objective, 

measurable characteristics should direct the analyst into the correct classification.

Evidence: SWGSTAIN terminology list/BPA language used in terminology

Why do we care about these problems?

Accurate conclusions regarding mechanisms are vital to a fair outcome in court.

What are the research questions?

1) How do BPA analysts currently classify patterns?

2) Find the characteristics of individual patterns that are relevant to pattern classification.

3) How much variation is there in classification among different BPA analysts?

4) What terms do we need to describe a bloodstained area in an objective and unambiguous way? 

(Find data descriptors that describe relevant bloodstain characteristics in a physical measurable 

way)
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5) Find a universal way to articulate pattern classification in order to come to the same outcome 

for all trained analysts.