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Frequently Asked Questions
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What is
SWGFAST? |
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Answer: An
organization that establishes consensus guidelines and
standards for the forensic examination of fingerprints, palm
prints and foot prints. It was established in 1995 as one of
several forensic science Scientific Working Groups (SWG).
The overall intent of Scientific Working Groups is to
improve forensic science practices and build consensus
amongst federal, state, local and private forensic
laboratories and practitioners. Published SWG guidelines and
standards are widely recognized by the forensic community,
the courts, and the forensic laboratory accrediting bodies.
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What are
the legal rules for allowing expert witness testimony? |
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Answer: Federal and state courts have
minimum qualifications for expert testimony. Federal Rules
of Evidence 702 states:
If scientific, technical or other specialized knowledge
will assist the trier of fact to understand the evidence or
to determine a fact in issue, a witness qualified as an
expert by knowledge, skill, experience, training or
education, may testify thereto in the form of an opinion or
otherwise, provided that (1) the testimony is based upon
sufficient facts or data, (2) the testimony is the product
of reliable principles and methods, and (3) the witness has
applied the principles and methods reliably to the facts of
the case. |
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What are the U.S. Supreme Court decisions related to the Daubert, Kumho & Joiner "trilogy"? |
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Answer: The
Daubert
Opinion States that the trial judge must still screen
scientific evidence to ensure it is relevant and reliable;
“The focus, of course, must
be solely on principles and methodology, not on the
conclusions they generate.”
Factors the court should consider
include: Testing and validation, Peer review, Rate of error,
“general acceptance”
Answer 2: Kumho
decided that the same criteria for
Daubert
applies to both technical and specialized knowledge referred
to in FRE 702. Joiner
expands the criteria to include the relevance and
reliability of the scientific evidence. |
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What are
the minimum qualifications for a Friction
Ridge Examiner? |
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Is
fingerprint examination a science? |
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| Answer: Yes. Fingerprint examination is
an applied science based upon the foundation of biological
uniqueness, persistence, and empirical validation through
observation. This is supported by the Daubert and Kumho
decisions. |
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Is
fingerprint examination reliable? |
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| Answer: Yes. The scientific basis and
methodology of fingerprint examination is reliable. The
reliability of fingerprint examination is supported by the
principles of biological uniqueness and persistence,
probability modeling, and empirical data gained through over
one hundred years of operational experience. |
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Can
mistakes be made in fingerprint examination? |
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Can
an error rate be defined for erroneous identifications (false
positives) in friction ridge examination? |
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| Answer: There are many definitions of
error and many variables when calculating error rates. In
regards to friction ridge examination error rate, the US
Supreme Court in Daubert v. Dow states that, “…the focus, of
course, must be solely on principles and methodology, not on
the conclusions they generate.” Others claim that the method
cannot be separated from the examiner and therefore they
must be combined. Examples of discovered error rates, that
an examiner may testify to, include: 1) personal erroneous
identification rate, 2) laboratory erroneous identification
rate, 3) estimated industry erroneous identification rate
(based on the approximate number of detected errors;
compared to the approximate number of examinations conducted
to date). |
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Why were there so many errors in the 1995 & 1998
Collaborative Testing Service (CTS) latent print proficiency
tests? |
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| Answer: The CTS proficiency tests are
not limited to only qualified fingerprint practitioners.
There were no test controls over who took the test, the test
environment, time constraints, or individual vs. group
performance results. Other factors included but were not
limited to the lack of understanding by the participants of
the new testing process or use of its results. Non-answers,
erroneous individualizations, missed individualizations, and
clerical mistakes were considered equal errors to the test
provider. |
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What is the standard for friction ridge identification
(individualization)? |
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Answer: The standard for
individualization is agreement of sufficient friction ridge
details in sequence when the following conditions have been
satisfied:
• Determined by a competent examiner, and
• Applied to a common area in both impressions, and
• Based on quantity and quality of the friction ridge
details, and
• Absent any discrepancy, and
• Reproducible conclusion
Answer 2: SWGFAST has published standards for all
conclusions. |
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How can two experts have different opinions on the same images? |
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Answer: Two experts may reach
differing conclusions. Two experts having the same level
of training, experience, and ability should reach the same
conclusion. There are three types of differing
conclusions:
1) Value versus no value
2) Individualization versus inconclusive
3) Exclusion versus inconclusive
4) Individualization versus exclusion
Errors can be minimized by the systematic verification of
reported conclusions, according to agency policy.
(See also the SWGFAST
Quality Assurance Guidelines for Latent Print Examiners)
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What is the definition of AFIS "lights-out" and does this process result in matches? |
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| Answer: The term “lights-out” means an
AFIS non-human process or workflow that is completely
automated. This type of result is possible because of
score-based algorithms that are able to automatically
process some deliberately-recorded fingerprints that score
above a pre-defined agency-specific threshold. Some agencies
do not employ lights-out processes, and those that do have a
wide range of score thresholds that result in human
intervention. |
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Can AFIS always make automated fingerprint matches? |
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| Answer: No. Often, deliberately recorded
fingerprints are not high enough quality to achieve a score
above a “lights-out” threshold. Additionally, latent prints
currently return a ranked order of candidates based upon the
position, location and direction of friction ridge features.
A friction ridge examiner makes a decision of
individualization or exclusion using the application of the
ACE-V methodology which cannot be automated. |
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What is the National Academy of Sciences? |
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| Answer: “The
National Academy of
Sciences (NAS) is an honorific society of distinguished
scholars engaged in scientific and engineering research,
dedicated to the furtherance of science and technology and
to their use for the general welfare.” |
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What is the "NAS Report"? |
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| Answer: The
Strengthening Forensic Science in the United States: A Path
Forward report was published in February, 2009 by the
Committee on Identifying the Needs of the Forensic Sciences
Community; Committee on Applied and Theoretical Statistics,
National Research Council. It contained 13 recommendations
to improve the forensic science disciplines. |
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Can fingerprints be identified with absolute certainty? |
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Answer: This is currently an issue that
is heavily debated in the community. To reject the
possibility of alternative hypotheses is unscientific
because science is always open to new information. However,
since fingerprint examination culminates with opinion
testimony, the lack of the examiner’s doubt is often
expressed as relative certainty in his or her conclusion.
Current research is attempting to quantify distinctiveness
and validate statistical and probability models that support
the examiner’s conclusion. There are several online
resources for additional information on this topic:
http://www.henrytempleman.com/
www.forensic.gov.uk
www.unil.ch/esc |
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Have statistical models been created for fingerprint identification? |
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| Answer: Yes, there have been over 20
models proposed over the last century that are related to
fingerprint identification. However, none of them take into
account everything that an examiner would consider during
the examination process and therefore each of them have
limitations. |
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What is certification and why is it important? |
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Answer: Certification, as it relates to
friction ridge examiners, involves assessing the knowledge,
skill, and ability of an examiner to successfully complete
an examination and demonstrate competency. Those lacking
certification are not generally precluded from practicing or
working in their respective disciplines.
Certification is important because it establishes a baseline
of knowledge and allows external entities, who are not
familiar with the discipline, to be assured of the skill
level of the practitioner. The NAS report made strong
recommendations for practitioners to achieve certification.
The main external certifying body for friction ridge
examiners is the International Association for
Identification (IAI), and some agencies have internal
certification programs. |
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Why is SWGFAST setting standards instead of guidelines? |
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| SWGFAST was originally founded as a
technical working group consisting of latent print examiners
to create consensus guidelines as best practices within the
friction ridge community. In the current climate, there has
been a call by the fingerprint community, legal community
and the NAS for more standardization. SWGFAST recognizes the
importance of laboratory compliance with minimum standards,
and is responding to this call by transitioning many of the
SWGFAST guideline documents to standards. |
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Is my agency required to adopt SWGFAST standards? If we
do, then do we have to adhere to all sections of them? |
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| Answer: No, because SWGFAST currently
has no enforcement authority. However, SWGFAST guidelines
and standards are widely recognized by the forensic
community, the courts, and the forensic laboratory
accrediting bodies. The U.S. Senate Judiciary Committee is
currently considering implementing recommendations within
the NAS report, including potential enforcement mechanisms
for standards set by SWGFAST and the other Scientific
Working Groups. |
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Are there any online references for addressing legal or daubert-like questions that might come up during testimony, and helpful answers for those questions? |
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How is the suitability of a friction ridge impression measured? |
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Answering the question of suitability
requires that the purpose be defined. For example, whether a
friction ridge impression is suitable for retention as
evidence is a different question than whether it is suitable
for identification.
The question of suitability also involves a subjective
measurement of information. It is recognized that any
scientific endeavor is subject to human interpretation.
(For example, training, experience, visual acuity, talent,
external influences) In friction ridge
examination, what might appear as an objective threshold
even has subjective elements. For example, requiring a
minimum number of features to establish suitability for the
purpose of identification may appear objective, but how an
examiner defines a “feature” is still subjective. Scientific
objectivity is achieved through the reproducibility of
subjective conclusions by other examiners, within
established parameters.
See also the DRAFT SWGFAST Standards for Examining Friction Ridge
Impressions and Resulting Conclusions. |
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Are friction ridge examinations subject to bias? |
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Yes, bias exists in all human endeavors. Types of bias that
may occur include contextual, confirmation and cognitive.
(See the SWGFAST
Standard Terminology of Friction Ridge Examination) If
bias is not mitigated it can prevent objective consideration
of information. However, there are quality assurance
measures available to mitigate the effects of bias. |
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Does contextual information always cause bias? |
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No, there are times when information properly assists the
investigation. For example, knowing the surface on which a
latent print was developed can aid the examination of that
impression. The absence of contextual information can also
interfere with the interpretation of data. |
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Is ACE-V a process, method, or methodology? |
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Historically, the fingerprint discipline has used the terms
interchangeably. The examination sequence of ACE-V can vary
in its formality and detail. It can be a method when
prescribed by an agency which has an explicit policy
regarding its application, or it can be a process when only
a general description is provided. ACE-V is further
explained in the SWGFAST document, “Examining Friction Ridge
Impressions and Resulting Conclusions (Latent/Tenprint)”. |
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