NAS Report on Firearms Toolmarks

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Questions and Answers

What is the main purpose of the 2008 NAS report?

To provide an overall assessment of firearms identification as a discipline

To evaluate the admissibility of firearms-related toolmark evidence in legal proceedings

To assess the validity of the firearm and toolmark discipline

To investigate the uniqueness of firearms-related toolmarks (correct)

According to the 2008 NAS report, what has not yet been fully demonstrated?

The accuracy of ballistic imaging

The validity of the fundamental assumptions of uniqueness and reproducibility of firearms-related toolmarks (correct)

The reproducibility of firearms-related toolmarks

The reliability of toolmark evidence in legal proceedings

What is the context of the statement about the validity of the fundamental assumptions of uniqueness and reproducibility?

General firearms identification

Ballistic imaging

Absolute exclusions (correct)

Legal proceedings

What does the 2008 NAS report explicitly state it is not?

An assessment of the validity of firearms identification as a discipline Signup and view all the answers

What topics are not within the charge of the committee according to the 2008 NAS report?

The admissibility of firearms-related toolmark evidence in legal proceedings and the validity of firearms identification as a discipline Signup and view all the answers

What is the underlying question of the committee's tasks?

Whether firearms-related toolmarks are unique Signup and view all the answers

What was the limitation of PCAST's preferred study design according to OSAC?

It was too narrow Signup and view all the answers

What was unique about many of the validation studies used by the firearms and toolmark profession?

They used consecutively manufactured firearms Signup and view all the answers

What was a limitation of the Baldwin et al study test design?

It did not mimic casework situations Signup and view all the answers

What was a challenge of using other studies for error rate discussions?

They had difficulty in calculating error rates Signup and view all the answers

What was a benefit of the Baldwin et al study test design?

It allowed for precise and easy error rate calculations Signup and view all the answers

What was a characteristic of typical casework situations?

Examiners inter-compared numerous items all at once Signup and view all the answers

What was the goal of using consecutively manufactured firearms in validation studies?

To create error-rate tests with worst-case scenario samples Signup and view all the answers

How did the error rate of the validation studies turn out?

There were few false identifications Signup and view all the answers

What is the primary issue with relying solely on the PCAST report to judge the validity of firearms and toolmarks?

The analysis contained within the report is flawed. Signup and view all the answers

How many papers are listed under the firearms and toolmarks section in the PCAST report?

417 Signup and view all the answers

What is the significance of the sentence 'PCAST members and staff identified and reviewed those papers that were relevant to establishing scientific validity'?

It implies that only certain papers were considered relevant. Signup and view all the answers

What is the outcome of PCAST's narrow definition of empirical research and validity?

The disregard of hundreds of research papers. Signup and view all the answers

What sources were used to compile the list of papers in the PCAST report?

Bibliographies, submissions, and literature searches. Signup and view all the answers

How many error rate studies were ultimately considered by PCAST?

9 Signup and view all the answers

What is implied by the listing of 417 references in the PCAST report?

A thorough consideration of the peer-reviewed literature. Signup and view all the answers

What is the role of PCAST members and staff in the review process?

They identified and reviewed papers relevant to establishing scientific validity. Signup and view all the answers

What is the main reason why OSAC FTS's argument is considered unconvincing?

It fails to recognize the inconsistencies between set-based designs and black-box studies Signup and view all the answers

What is the main concern of the key conclusions presented in court?

The ability to accurately associate ammunition with a specific gun Signup and view all the answers

What is the criticism of PCAST's response to the OSAC firearms subcommittee?

It failed to address the four major points of disagreement Signup and view all the answers

What is the concern about estimating error rates from historical performance on proficiency tests?

It is almost certain to yield wrong values Signup and view all the answers

What was the conclusion of Dr. Budowle and colleagues in a peer-reviewed article?

Error rates from studies should not be required with examiner testimony Signup and view all the answers

What was PCAST's stance on requiring error rates from studies with examiner testimony?

It was insisted upon despite previous rejection Signup and view all the answers

Why is it unlikely for a laboratory to make the same error again?

Because errors are discovered and investigated thoroughly Signup and view all the answers

What was the main purpose of the National Academy of Sciences report in 1996?

To caution against deriving an industry-wide error rate Signup and view all the answers

What is a common way the reports issued by the NAS and PCAST have been used in court trials?

To support the consensus view of 'real scientists' or 'academia' Signup and view all the answers

What is the result of careful reading of the reports, such as PCAST?

Identification of the misrepresentations and errors that remain uncorrected Signup and view all the answers

Why do critics avoid discussing certain aspects of the PCAST report?

Because they contradict their own views on error rate calculations and inconclusive results Signup and view all the answers

What is the implication of the research performed by academia and non-practitioner individuals?

That examiners can reliably interpret similarities and differences and render accurate common source determinations Signup and view all the answers

What is the tone of the PCAST report, according to critics who rely on it?

Appropriately critical of the discipline Signup and view all the answers

What is the purpose of highlighting the misrepresentations and errors in the reports?

To promote a more accurate understanding of the reports' findings Signup and view all the answers

What is the relationship between the PCAST report and critics' views on error rate calculations and inconclusive results?

The PCAST report is often ignored by critics when it comes to these topics Signup and view all the answers

What is the significance of the research performed by academia and non-practitioner individuals in the context of firearm and toolmark evidence?

It provides objective data that supports the fundamentals of firearm and toolmarks examination Signup and view all the answers

Study Notes

NAS Report (2008)

The report explicitly states that it should not be used to measure the validity of the firearm and toolmark discipline.
The report does not provide an overall assessment of firearms identification as a discipline nor advises on the admissibility of firearms-related toolmark evidence in legal proceedings.

Ballistic Imaging

Critic Point 1: The validity of the fundamental assumptions of uniqueness and reproducibility of firearms-related toolmarks has not yet been fully demonstrated.
Context: This statement was made in the context of absolute exclusions, which refers to whether a particular set of toolmarks can be shown to come from one weapon to the exclusion of all others.

PCAST Report

The report lists 417 citations under the firearms and toolmarks section, but only reviewed papers that were relevant to establishing scientific validity.
The report's analysis is flawed, and its narrow definition of empirical research and validity led to the disregard of hundreds of research papers.
Only nine error rate studies were considered, and one pair of knowns did not have a corresponding unknown, and two unknowns did not have a corresponding known.

PCAST Issues

Issue 3: OSAC concluded that PCAST's preferred study design was too narrow, and other types of studies have value in assessing overall error.
The Baldwin study did not mimic casework situations like other studies did, and OSAC's view was that each validation study provides independent data points that show a low overall error rate.
Issue 4: PCAST insisted that error rates from studies be required with examiner testimony, but this practice had already been considered and logically rejected.
The National Academy of Sciences report (1996) cautioned against attempting to derive an industry-wide error rate from historical performance on proficiency tests, as it is almost certain to yield wrong values.

Misinterpretation and Misrepresentation

The reports issued by the NAS and PCAST have been misinterpreted and misrepresented in declarations offered to the courts as well as in court trials by attorneys.
The reports are sometimes held up as the consensus view of “real scientists” or of “academia,” but this ignores the wealth of research performed by academia and non-practitioner individuals that has demonstrated the fundamentals of firearm and toolmarks examination.

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Description

The 2008 NAS report clarifies its purpose and limitations, emphasizing that it does not evaluate the validity of the firearm and toolmark discipline. The report focuses on specific aspects, rather than providing an overall assessment of firearms identification as a discipline.