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Updated 2 October 2012
  Frequently Asked Questions
What is SWGFAST?
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.
What are the legal rules for allowing expert witness testimony?
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.
What are the U.S. Supreme Court decisions related to the Daubert, Kumho & Joiner "trilogy"?
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.
What are the minimum qualifications for a Friction Ridge Examiner?
Answer: Legally, the judge decides who is qualified to present expert testimony.

Answer 2: SWGFAST established the following documents:
Standards for Minimum Qualifications and Training to Competency for Friction Ridge Examiners (Latent/Tenprint)
Quality Assurance Guidelines for Latent Print Examiners

Answer 3: An individual who adheres to the above guidelines should be able to qualify as an expert in a court of law.
Is fingerprint examination a science?
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.
Is fingerprint examination reliable?
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.
Can mistakes be made in fingerprint examination?
Answer: Yes. In any human endeavor, there is a potential for error. Adherence to SWGFAST Standards for Minimum Qualifications and Training to Competency for Friction Ridge Examiners (Latent/Tenprint) and quality assurance minimize the risk of human error.
Can an error rate be defined for erroneous identifications (false positives) in friction ridge examination?
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).
Why were there so many errors in the 1995 & 1998 Collaborative Testing Service (CTS) latent print proficiency tests?
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.
What is the standard for friction ridge identification (individualization)?
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.
How can two experts have different opinions on the same images?
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)
What is the definition of AFIS "lights-out" and does this process result in matches?
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.
Can AFIS always make automated fingerprint matches?
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.
What is the National Academy of Sciences?
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.”
What is the "NAS Report"?
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.
Can fingerprints be identified with absolute certainty?
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:
Have statistical models been created for fingerprint identification?
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.
What is certification and why is it important?
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.
Why is SWGFAST setting standards instead of guidelines?
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.
Is my agency required to adopt SWGFAST standards? If we do, then do we have to adhere to all sections of them?
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.
Are there any online references for addressing legal or daubert-like questions that might come up during testimony, and helpful answers for those questions?
How is the suitability of a friction ridge impression measured?
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.
Are friction ridge examinations subject to bias?
Does contextual information always cause bias?
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.
Is ACE-V a process, method, or methodology?
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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