Since
1995, SWGFAST has been establishing guidelines for the development and
enhancement of friction ridge examiners' knowledge, skills and
abilities. Although sponsored by the FBI Laboratory, SWGFAST
members
are from federal, state and local forensic science laboratories as well
as from private practice. Approved Guidelines, Draft for
Comment Guidelines, Position Statements, Bylaws and other information
are available online at www.swgfast.org.
This
Press Kit is designed to provide credible responses to common questions
about friction ridge examination (also known as latent print
examination). This information is not presented as an indepth
academic
discussion and does not address all aspects of the below
topics. Comments and additional questions recommended for
discussion at this website are invited. Please contact the
SWGFAST Executive
Secretary.
1. Expert Testimony Rules of Evidence
1.1 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.
2 US Supreme Court decisions; Daubert and Kumho
2.1 Daubert Opinion
States that:
2.1.1 The trial
judge must still screen scientific evidence to ensure it is relevant
and reliable;
2.1.2 “The focus, of
course, must be solely on principles and methodology, not on the
conclusions they generate”
2.1.3 Factors the
court should consider include:
2.1.3.1 – testing and
validation
2.1.3.2 – peer review
2.1.3.3 – rate of error
2.1.3.4 – “general acceptance”
2.2 Kumho decided
that the same criteria for Daubert applies to both technical and
specialized knowledge referred to in FRE 702.
3. What are the minimum qualifications for a latent print
expert?
3.1 Legally, the judge decides who is
qualified to present expert testimony.
3.2 SWGFAST established:
3.3 An individual who
adheres to the above guidelines should be able to qualify as an expert
in a court of law.
4 What is an expert opinion?
4.1 As defined in Federal
Rule 702, expert conclusions are presented as opinion testimony.
Fingerprint conclusions are not based upon personal bias but are
founded on the application of scientific methods.
5 Are fingerprints a science?
5.1 Yes.
Fingerprint examination is an applied science based upon the foundation
of biological uniqueness, permanence, and empirical validation through
observation.
5.2 This is supported by
the Daubert and Kumho decisions.
6 Are fingerprints reliable?
6.1 Yes. The scientific
basis and methodology of fingerprint examination is totally reliable.
6.2 Reliability of
fingerprint examination is supported by the theories of biological
uniqueness and permanence, probability modeling, and empirical data
gained through over one hundred years of operational experience.
7 Can mistakes be made in the examination of
fingerprints?
7.1 Yes. In any
human endeavor, there is a potential for error. Adherence to
SWGFAST guidelines for training
and quality
assurance minimize the risk for human error. Human error
should not be confused with methodological or scientific error.
8 What types of human errors can occur in
fingerprints?
8.1 There are two main
types of human
errors. The first and most serious is the erroneous
individualization.
8.1.1 This occurs when
the fingerprint is attributed to the wrong person.
8.2 The second error is
the missed individualization.
8.2.1 This occurs when
the fingerprint is not individualized when it should have been.
9 What is the difference between what Daubert
considers an error rate for fingerprint identification and what critics
attempt to define as an error rate?
9.1 Daubert looks only at
the error rate of the method, not the error rate of the practitioner
(human error).
9.1.1 The US Supreme
Court states in Daubert that, “…the focus, of course, must be solely on
principles and methodology, not on the conclusions
they generate .”
9.2 Some attempt to
include practitioner error rate.
9.2.1 Per the National
Academy of Sciences , a compilation of practitioner errors should not
be construed as an error rate of the methodology.
9.2.1.1 An individual’s
error rate only applies to that person and not the community of
practitioners or the science.
9.3 During the
qualification phase to determine expertise, an individual’s error rate
is a valid consideration by the court.
10 Why were there so many errors in the 1995 &
1998 Collaborative Testing Service (CTS) latent print proficiency tests?
10.1 The CTS proficiency
tests are not limited to only qualified fingerprint practitioners.
10.2 There were no test
controls over:
10.2.1 Who took the test;
10.2.2 Test environment;
10.2.3 Time constraints;
10.2.4 Individual vs.
group performance results.
10.3 Other factors
include but are not limited to:
10.3.1 Lack of
understanding by the participants of the new testing process or use of
its results;
10.3.2 Non-answers,
erroneous individualizations, missed individualizations, and clerical
mistakes were considered equal errors.
11 What is the standard for fingerprint
identification (also sometimes referred to individualization)?
11.1 The standard for
individualization is agreement of sufficient friction ridge details in
sequence when the following conditions have been satisfied:
11.1.1 Determined
by a competent
examiner, and
11.1.2 Applied to a
common area in both impressions, and
11.1.3 Based on quantity
and quality of the friction ridge details, and
11.1.4 Absent any
discrepancy, and
11.1.5 Reproducible
conclusion
11.2 SWGFAST has
published standards for all conclusions.
12 Why are there only 3 possible conclusions to a
fingerprint comparison?
12.1 Fingerprints are
unique and can be attributed to only one source.
12.1.1 A conclusion will
be individualization, exclusion (not identified), or an
inconclusive.
12.2 Statements of
possible, probable, or likely fingerprint conclusions are speculative,
unscientific, inappropriate and misleading.
13 How can two experts have different opinions?
13.1 Two experts having
different levels of training, experience, and ability may reach
differing (but not conflicting) conclusions.
13.1.1 Two experts may
differ in opinions between inconclusive and individualization or
between inconclusive and exclusion.
13.2 Two experts having
the same level of training, experience, and ability should reach the
same conclusion.
13.3 Conflicting expert
opinions of individualization and exclusion to the same fingerprint
denotes an error on the part of one expert.
14 Does an AFIS make latent print identifications?
14.1 No. The Automated
Fingerprint Identification System (AFIS) is a computer based search
system but does not make a latent print individualization decision.
14.1.1 AFIS provides a
ranked order of candidates based upon search parameters.
14.1.2 A latent print
examiner makes the decision of individualization or exclusion from the
candidate list.
14.1.3 The practice of
relying on current AFIS technology to individualize latent prints
correctly is not sound.
15 Can an AFIS make ten print identifications?
15.1 No. However, some
agencies have implemented procedure(s) allowing tenprint criminal
history updates without human intervention.
15.1.1 A ten print record
has an abundance of information to support this procedure.
15.1.2 Questions of
accuracy require a comparison by a qualified fingerprint examiner.
16 Did the NIJ 2000 solicitation on fingerprints
indicate that validation was needed?
16.1 Yes.
Continuing validation of existing forensic sciences is always desirable.
16.2 The NIJ offered a
letter dated June 2000, which clearly explained the intent of the solicitation. The grant
funding was recalled and the solicitation was rewritten to include all
pattern evidence sciences.
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