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Standard Guide for

Developing Discipline Specific Methodology for ACE-V

Standard Guide for

Developing Discipline 

Specific Methodology for 

ACE-V

Virtual Subcommittee #3: ACE-V Process Map

Chemistry/Instrumental Analysis, Digital/Multimedia, and Physics/Pattern 

Interpretation Scientific Area Committees

Organization of Scientific Area Committees (OSAC) for Forensic Science
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Standard Guide for

Developing Discipline Specific Methodology for ACE-V

OSAC Proposed Standard

Standard Guide for

Developing Discipline Specific 

Methodology for ACE-V

Prepared by

Virtual Subcommittee #3: ACE-V Process Map

Version: 1.0

[March 2020]

Disclaimer:

This document has been developed by the Virtual Subcommittee #3: ACE-V Process Map of the 

Organization of Scientific Area Committees (OSAC) for Forensic Science through a consensus 

process and is proposed for further development through a Standard Developing Organization 

(SDO). This document is being made available so that the forensic science community and 

interested parties can consider the recommendations of the OSAC pertaining to applicable 

forensic science practices. The document was developed with input from experts in a broad 

array of forensic science disciplines as well as scientific research, measurement science, 

statistics, law, and policy. 

This document has not been published by a SDO. Its contents are subject to change during the 

standards development process. All interested groups or individuals are strongly encouraged to 

submit comments on this proposed document during the open comment period administered by 

the ASTM International, Committee E30 on Forensic Science. 

 
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Standard Guide for

Developing Discipline Specific Methodology for ACE-V

Date: 03/22/2020

Ballot Action: New standard guide for consideration 

Rationale: This document was developed at the request of the OSAC 

Physics/Pattern Interpretation SAC. The ACE-V Virtual Interdisciplinary 

subcommittee #3 was established that consisted of the 

Chemistry/Instrumental Analysis and Digital/Multimedia SAC’s. Each of 

the following SC’s were involved and provided comments that were 

adjudicated: Facial Identification, Fire Debris and Explosives, Firearms

and Tool marks, Footwear and Tire, Friction Ridge, Video Imaging 

Technology and Analysis, and Materials. The document was selected to be 

further developed by ASTM. The intent of this guide is to establish a 

framework for developing a forensic discipline-specific methodology, to 

govern standardized methods used to conduct the various phases of ACE-V 

in the relevant disciplines. Each discipline could then develop their own 

standards that describe specific requirements unique to that discipline.

Standard Guide for

Developing Discipline Specific Methodology for ACE-V1

This standard is issued under the fixed designation X XXXX; the number immediately following the designation indicates 

the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the 

year of last reapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval. 

1. Scope

1.1 This guide identifies and defines the various phases within the methodology of ACE-V.

1.2 It specifies minimum general requirements that shall be adhered to for a methodology to 

be recognized as ACE-V

1.3 This guide does not define any discipline specific test methods.

1.4 Units - The values stated in SI units are to be regarded as the standard. No other units of 

measurement are included in this standard.

1.5 This standard does not purport to address all of the safety concerns, if any, associated 

with its use. It is the responsibility of the user of this standard to establish appropriate safety and 

health practices and determine the applicability of regulatory limitations prior to use.

1.6 This standard cannot replace knowledge, skills, or abilities acquired through education, 

training, and experience (E2917), and is to be used in conjunction with professional judgment by 

individuals with such discipline-specific knowledge, skills, and abilities.

2. Referenced Documents

2.1 ASTM Standards2:

1 This practice is under the jurisdiction of ASTM Committee XXX and is the direct responsibility of Subcommittee XXX. 

Current edition approved XXX XX, XXXX. Published XXX XXXX. DOI: 10.1520/XXXXX-XX.

2 For referenced ASTM standards, visit the ASTM website, www.astm.org or contact ASTM Customer Service at Service@astm.org. For the 

Annual Book of ASTM standards volume information, refer the standard’s Document Summary page on the ASTM website.
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Standard Guide for

Developing Discipline Specific Methodology for ACE-V

2.1.1 ASTM E2917-19a, Standard Practice for Forensic Science Practitioner Training, 

Continuing Education, and Professional Development Programs, ASTM International, West 

Conshohocken, PA, 2019.

2.2 ISO Standards3:

2.2.1 ISO 21043-1:2018 (E), Forensic Sciences - Part 1: Terms and Definitions.

2.2.2 ISO 9000:2015 (E), Quality Management Systems - Fundamentals and Vocabulary.

2.2.3 ISO 9001: 2015 (E), Quality Management Systems - Requirements.

2.2.4 ISO/IEC 17025:2017 (E), General requirements for the competence of testing and 

calibration laboratories.

3. Terminology

3.1 Definitions:

3.1.1 item, n - object, substance or material that is collected, derived or sampled as part of the 

forensic process as defined in ISO 21043-1:2018(E).

3.1.2 reference specimen, n - material from a known source (NOTE 1) used for comparison 

purposes in a forensic process as defined in ISO 21043-1:2018(E).

NOTE 1: Source may refer to a specific person (for example, an individual whose face appears in 

an image, a recorded voice, or a sample of handwriting); a specific part of the body of an individual 

(for example, the finger that produced a latent print); a specific object (for example, a firearm, a 

shoe, or a typewriter); or a location (for example, a building visible in the background of an image). 

3.1.3 Verification, n - Confirmation, through the provision of objective evidence that specified 

requirements have been fulfilled as defined in ISO 9000:2015 (E).

4. Summary of Practice

4.1 Define the type of items and reference specimen

4.2 Describe the Acceptance criteria

4.3 Describe Requirements for Conducting Analysis

4.4 Describe Requirements for Conducting Comparisons.

4.5 Describe the requirements for conducting the Evaluation Phase.

4.6 Describe the requirements for conducting Verification

4.7 Specify the minimum requirements for Reporting of Results.

4.8 Specify the minimum requirements for Technical Records to be retained.

3 For referenced ISO standards, visit the ANSI website, https://webstore.ansi.org/
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Standard Guide for

Developing Discipline Specific Methodology for ACE-V

(7.4)

Describe Requirements 

for Conducting Analysis

The step during which a 

forensic examiner 

considers the unknown 

item and/or reference 

sample in terms of it s 

properties, features or 

characteristics, to assess 

whether a given item is 

suitable for Comparison.

(7.1)

START

Initiator: Need to 

Develop a Discipline 

Specific Standard for 

ACE-V

(7.5)

Describe Requirements 

for Conducting 

Comparisons

The step during which a 

forensic examiner 

compares/measures the 

available data in two 

items, to facilitate the 

decision-making process 

during the Evaluation 

phase

(7.6)

Describe the 

requirements for 

conducting the Evaluation 

Phase

The step during which an 

examiner evaluates the 

clarity, quantity, 

specificity, reproducibility, 

persistence, and extent of 

similarities, dissimilarities 

and expected variations of 

the observed data to form 

a conclusion.

(7.1 0)

END

Product: Discipline 

Specific Standard 

FOR ACE-V

(7.7)

Describe the 

requirements for 

conducting 

Verification: Defined 

in ISO 9000:2015(E), 

3.8.1 2, as 

confirmation, 

through the provision 

of objective evidence, 

that specified 

requirements have 

been fulfilled

(7.2)

Define the type of 

items and 

reference 

specimen

(7.3)

Describe the 

Acceptance 

criteria

(7.9)

Specify the 

minimum 

requirements for 

Technical Records to 

be retained:

The ISO/IEC 

17025:2017(E), 7.5, 

provide detailed 

guidance.

(7.8)

Specify the 

minimum 

requirements for 

Reporting of 

Results:

The ISO/IEC 

17025:2017(E), 7.8, 

provide detailed 

guidance.

Fig. 1 High-Level Framework for Developing Discipline Specific Standards For ACE-V.

5. Significance and Use

5.1 This guide impacts and applies to forensic disciplines that identify the need to develop 

discipline specific standards for the application of the methodology of ACE-V (Analyze, Compare, 

Evaluate and Verify).

5.2 This guide provides a framework for developing a forensic discipline-specific 

methodology, to govern standardized methods used to conduct the various phases of ACE-V in 

the relevant discipline. 

5.3 Application of the requirements in this guide will lead to inter disciplinary standardized 

methodology which can then be validated through empirical studies within each of the various 

forensic disciplines involved in conducting feature comparisons.

6. General Requirements 

6.1 Develop discipline specific standards for ACE-V following the framework presented in 

this guide.

6.2 Clearly define the methods used, and criteria applied in each step of ACE-V.

6.3 Specify those steps in a procedure where the sequence of the steps is critical to the 

outcome of the test (NOTE 2) and specify the minimum requirements for documentation to be 

retained in the Technical record in this regard. 

NOTE 2: For example, this is particularly relevant where the discipline applies bias reduction 

procedures such as "linear-ACE-V" or "linear sequential unmasking" to reduce bias.
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Standard Guide for

Developing Discipline Specific Methodology for ACE-V

6.4 Provide information regarding the validation of methods selected for inclusion in the 

discipline specific standard. Those methods that will be used in Testing Laboratories, shall 

adhere to the method verification and validation requirements as per ISO/IEC 17025 and ISO 

9001: 2015. These standards provide direction on the Quality management systems requirements 

for design and development of products and services, specifically with regards to design and 

development controls such as verification and validation.

7. Procedure

7.1 Initiator: The procedure described in this guide is initiated when the need exists to 

Develop a Discipline Specific Standard for ACE-V.

7.2 Define the type of items (NOTE 3) and reference specimens that will be accepted for 

testing in the specific discipline.

NOTE 3: Examples of items are: Hinge lifters or digital images containing friction ridge 

impressions, recovered video or images that recorded a subject of interest, electrostatic dust lifts 

or three-dimensional casts containing footwear impressions.

7.3 Describe the Acceptance criteria: Each discipline specific standard shall describe the 

minimum acceptance criteria (NOTE 4) to which the items must adhere before being accepted 

for testing. 

NOTE 4: Examples of acceptance criteria are clarity of digital images, minimum resolution 

requirements for digital images as applicable to the discipline, clarity and other variables of 

digital images and video, proper packaging to prevent contamination and cross contamination, 

minimum quality requirements for reference specimens.

7.4 Describe Requirements for Conducting Analysis: Analysis is a step in the ACE-V 

Methodology during which a forensic practinioner considers the unknown item and/or known 

reference specimen in terms of its properties, features, or characteristics, which may be directly 

observable, measurable, or otherwise perceptible qualities, to assess whether a given item is 

suitable for potential Comparison. Clearly define and describe the following aspects of the 

Analysis step for each discipline specific standard to include at a minimum:

7.4.1 Measurable, observable, demonstrable data, features (NOTE 5) or characteristics that 

will be considered to provide objective evidence that the specified requirement to reach a 

suitability decision has been met.

NOTE 5: Examples of features are class characteristics in footwear comparisons, facial features, 

different levels of detail in the friction ridge impressions or striations on cartridge casings that 

will be considered during comparisons.

7.4.2 The specific methods (NOTE 6) to be used during the Analysis step.

NOTE 6: Examples of methods for analysis are visual examination of items under different 

levels of magnification, microscopy, spectrometry, application of automated database searches to 

detect features and apply suitability values, and micrometry to detect features or characteristics 

that can be utilized for comparison.

7.4.3 The criteria necessary to determine that the specified requirement for a suitability 

decision is reached. 
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Standard Guide for

Developing Discipline Specific Methodology for ACE-V

7.5 Describe the Requirements for Conducting Comparisons: Comparison is a step in the 

ACE-V Methodology during which a forensic practitioner compares or measures the available 

data (properties, features, or characteristics, which may be directly observable, measurable, or 

otherwise perceptible qualities) in two items, to facilitate the decision-making process during the 

Evaluation phase. Clearly define and describe the following aspects of the Comparison step for 

each discipline specific standard to include at a minimum:

7.5.1 The specific methods (NOTE 7) to be used during the Comparison step.

NOTE 7: Examples of methods of comparison include using a comparison microscope in 

firearms examination, visual side by side comparison in friction ridge examination and image 

analysis, mass spectrometry, creating overlays in footwear comparison. Also automated systems 

like “Case specific Biometric Databases” to conduct comparisons with small populations of 

known reference specimens.

7.5.2 The instruments used during the Comparison step, and where applicable, minimum 

manufacturing and calibration requirements for specific instruments.

7.6 Describe the requirements for conducting the Evaluation Phase: Evaluation is a step 

in the ACE-V Methodology during which the forensic practitioner evaluates the clarity, quantity, 

specificity, reproducibility, persistence, and extent of similarities, dissimilarities and expected 

variations of the observed data (properties, features, or characteristics, which may be directly 

observable, measurable, or otherwise perceptible qualities), taking into account any potential 

limitations of the items, to form a conclusion. Clearly define and describe the following aspects 

of the Evaluation step for each discipline specific standard, to include at a minimum:

7.6.1 The method (NOTE 8) to be used during the Evaluation step for interpreting the data or 

providing the weight of the observations.

NOTE 8: For example, for source conclusions, the examiner assesses the weight of observations 

by considering the prospect of finding the observed characteristics if the items came from the 

same source, as well as the prospect of finding the observed characteristics if the items came 

from different sources. This should include the application of statistical models where applicable.

7.6.2 The range of possible conclusions.

7.6.3 The criteria (NOTE 9) necessary to determine the specified requirement to reach each 

of the possible conclusions.

NOTE 9: It is important that standards specify not only the factors to be weighed, but also the 

threshold and criteria for reaching each possible conclusion.

7.6.4 Specify the circumstances (if any) under which it is appropriate to consider contextual 

information or investigative facts when drawing conclusions.

7.7 Describe the requirements for conducting Verification: Verification is defined in ISO 

9000:2015(E), as the confirmation through the provision of objective evidence, that specified 

requirements have been fulfilled. It is further defined in ISO/IEC 17025:2017(E), for testing and 

calibration Laboratories as: “provision of objective evidence that a given item fulfils specified 

requirements. “Item” is further described as: “The item may be, for example, a process, 

measurement procedure, material, compound, or measuring system”. Clearly define and describe 

the following aspects of the Verification Step for each discipline specific standard, to include at a 

minimum:

7.7.1 The various methods (NOTE 10) through which confirmation is obtained. 
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Standard Guide for

Developing Discipline Specific Methodology for ACE-V

NOTE 10: ISO 9000:2015(E) describes the process of confirmation as follows: “The objective 

evidence needed for a verification can be the result of an inspection or of other forms of 

determination such as performing alternative calculations or reviewing documents”. Documents 

are further defined as: “information and the medium on which it is contained”.

7.7.2 The objective evidence (NOTE 11) that the specified requirements have been met.

NOTE 11: ISO 9000:2015(E) defines objective evidence as: “data supporting the existence or 

verity of something” and indicates that: “Objective evidence can be obtained through 

observation, measurement, test, or by other means”

7.7.3 The specified requirements (NOTE 12) to be met for each result or conclusion. 

NOTE 12: ISO 9000:2015(E) defines “requirement” as: “need or expectation that is stated, 

generally implied or obligatory”. Also, that: “A specified requirement is one that is stated, for 

example in documented information”.

7.8 Specify the minimum requirements for Reporting of Results:

7.8.1 ISO/IEC 17025:2017(E) provides detailed guidance on Reporting requirements.

7.9 Specify the minimum requirements for Technical Records to be retained:

7.9.1 ISO/IEC 17025:2017(E) provide detailed guidance on requirements for Technical 

Records. At a minimum documentation should include in some manner, the features observed in 

each of the items to be compared.

7.9.2 Identify and include contextual information about matters other than the physical 

characteristics of the items being compared, that should be included in the documentation.

7.10 End: The procedure described in this guide ends when a Discipline Specific Standard 

for ACE-V is complete.

8. Keywords

8.1 ACE-V, analysis, comparison, evaluation, verification, methodology 
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Standard Guide for

Developing Discipline Specific Methodology for ACE-V

APPENDIX

(Nonmandatory Information)

X1. RATIONALE

X1.1 Following are references to some publications which provide a condensed historical 

overview on the evolution of the ACE-V Methodology:

X1.1.1 Champod (1)

4 states that pioneers in forensic science, although not named that way, 

were already applying a protocol similar to ACE-V, citing (Heindl 1927 (2) and Locard 1931 (3)). 

He recognizes the Royal Canadian Mounted Police (RCMP) as “...the organization that developed 

and adopted the ACE-V protocol for forensic comparisons...” referencing Huber (4). Chief Supt. 

R.A. Huber primarily addressed forensic document examiners with this publication. He was the 

Assistant Director, Laboratories and Identification Directorate, R.C.M.P. in Ottawa at the time. He 

recognized that various disciplines are following a similar process even though mostly 

subconsciously, e.g. in handwriting and firearms examinations. He also mentioned fingerprint, 

physical matching and chemical examinations. He described the three distinct phases of the ACE 

methodology as follows:

X1.1.1.1 “Analysis – The unknown item must be reduced to a matter of its properties or 

characteristics, which may be directly observable, measurable, or otherwise perceptible qualities.

X1.1.1.2 Comparison – The properties or characteristics of the unknown determined through 

Analysis are now compared with the familiar or recorded properties of known items.

X1.1.1.3 Evaluation – Similarities or dissimilarities in properties or characteristics will each 

have a certain value for identification purposes determined by its likelihood of occurrence. The 

weight or significance of each must therefore be considered.”

X1.1.2 Further on p.11 Huber (4) states: “Scientific method provides a fundamental criterion 

for conclusions drawn from it: that conclusions must be restricted to what one may expect to be 

the conclusions of any other competent scientist”, inferring what later became known as the 

“Verification” phase of ACE-V. 

X1.1.3 This methodology was also adopted by Cassidy (5) in the Footwear discipline in his 

publication in 1980. He added however that: “The inexperienced examiner should always have his 

identification work re-examined and confirmed by a qualified person”, re-enforcing the 

Verification concept.

X1.1.4 David Ashbaugh published several articles in the early 1990’s covering the 

methodology of ACE-V for friction ridge comparison, and extensively so in his publication in 

1999 (6).

X1.1.5 ACE-V was adopted by the Scientific Working Group for Friction Ridge Analysis, 

Study, and Technology (7) in 2002 as the standard for friction ridge examination. 

X1.1.6 John Vanderkolk discusses the application of ACE-V for Image Analysis, in great 

detail in his publication in 2009 (8). 

X1.1.7 ACE-V was published in 2015 in the Best Practice Manual for Fingerprint Examination 

issued by the European Network of Forensic Science Institutes (ENFSI) (9).

4 The boldface numbers in parentheses refer to the list of references at the end of this guide.
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Standard Guide for

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X1.1.8 ACE-V was cited as a possible accepted protocol applied to photographic comparisons 

in the Scientific Working Group on Digital Evidence (SWGDE) guideline Documents (10), (11) 

and technical overview document (12).

X1.2 The process of developing a discipline specific ACE-V standard is discussed in this guide 

following the High-Level Framework for Developing Discipline Specific Standards For ACE-V 

depicted in fig. 1.

BIBLIOGRAPHY

(1) Champod, C. Lennard, C., Margot, P., Stoilovic, M., Fingerprints and Other Ridge Skin 

Impressions, Second Edition. Boca Raton, CRC Press, Taylor & Francis Group, FL, 2016, 

Chapter 2, p. 34.

(2) Heindl, R., System und Praxis der Daktyloskopie, 3rd ed. Berlin Germany, Walter de Gruyter 

& Co., Vereinigung Wissenschaftlichen Verleger, 1927. 

(3) Locard, E., Traité de criminalistique, Joannes Desvigne et fils Editeurs, Lyon, France, 1931, 

vol. I à VII.

(4) Huber, R. A. “The Philosophy of Identification”, RCMP Gazette, July-August 1972.

(5) Cassidy, M. J., “Footwear Identification”, Public Relations Branch of the Royal Canadian 

Mounted Police, 1980, Chapter 5, p. 91,

(6) Ashbaugh, D. R., Qualitative-Quantitative Friction Ridge Analysis-An Introduction to Basic 

and Advanced Ridgeology, CRC Press, Boca Raton, FL, 1999.

(7) Scientific Working Group for Friction Ridge Analysis, Study, and Technology (SWGFAST), 

Document #10, Standards for Examining Friction Ridge Impressions and Resulting

Conclusions, 03/13/2013.

(8) Vanderkolk, John, Forensic Comparative Science: Qualitative Quantitative Source 

Determination of Unique Impressions, Images, and Objects, Academic Press, 20th July 2009 

(eBook ISBN: 97800809200; 16Hardcover ISBN: 9780123735829).

(9) European Network of Forensic Science Institutes, ENFSI, Best Practice Manual for 

Fingerprint Examination, ENFSI-BPM-FIN-01, Version 01. Chapter 6, p.13-16. 

(10) Scientific Working Group on Digital Evidence, SWGDE, Guidelines for Forensic Image 

Analysis, February 21, 2017, Version 1.0: 

https://www.swgde.org/documents/Current%20Documents/SWGDE%20Guidelines%20for%

20Forensic%20Image%20Analysis

(11) Scientific Working Group on Digital Evidence, SWGDE Technical Overview for Forensic 

Image Comparison, July 16, 2019, Version1.0: 

https://www.swgde.org/documents/Current%20Documents/SWGDE%20Technical%20Over

view%20for%20Forensic%20Image%20Comparison.

(12) Scientific Working Group on Digital Evidence, SWGDE Best Practices for Photographic 

Comparison for All Disciplines, July 18, 2017, Version 1.1: 

https://www.swgde.org/documents/Current%20Documents/SWGDE%20Best%20Practices%

20for%20Photographic%20Comparison%20for%20All%20Disciplines