Forensic Expert Witness: Courtroom Testimony in Forensic Science

These flashcards summarize key terms and concepts related to courtroom testimony in forensic science based on the provided lecture notes.

Define an expert witness and state the criteria by which an individual is qualified to provide expert testimony in forensic science.

An expert witness possesses specialized knowledge, training, education, or experience that enables interpretation of scientific or technical information beyond the understanding of a layperson.

State the purpose of expert testimony within the judicial process.

Expert testimony assists the trier of fact in understanding scientific principles, interpreting analytical results, and evaluating technical matters relevant to the case.

Describe the primary objectives of direct examination in forensic testimony.

Direct examination establishes the expert’s qualifications and elicits a clear explanation of analytical procedures, results, and conclusions.

Identify the central goal of cross examination in forensic science testimony.

Cross examination seeks to evaluate the reliability of the expert’s methods, challenge the expert’s conclusions, probe for inconsistencies, and assess potential bias.

Explain the professional rationale for conservative courtroom attire for forensic experts.

Conservative attire minimizes distraction, maintains credibility, and promotes focus on scientific testimony rather than personal appearance.

Define a subpoena duces tecum and specify its relevance to forensic testimony.

A subpoena duces tecum compels the expert to appear in court and produce all scientific records, including notes, reports, chain of custody documents, and supporting data.

Outline the essential components of pre testimony preparation for forensic scientists.

Preparation requires review of case notes, analytical data, laboratory procedures, chain of custody documentation, and personal qualifications.

State the legal function of the oath administered prior to testimony.

The oath binds the witness to provide truthful, complete, and accurate testimony under penalty of perjury.

Define voir dire in the context of expert witness qualification.

Voir dire is the process in which opposing counsel evaluates the expert’s qualifications before the judge determines admissibility of expert testimony.

Explain the importance of establishing chain of custody during testimony.

Chain of custody verifies the identity, integrity, and continuity of evidence from collection to analysis, ensuring admissibility and reliability.

Describe the nature of scientific challenges that may arise during cross examination.

Challenges may concern method validation, instrument reliability, error rates, analytical uncertainty, or interpretive limitations.

Define bias in the context of forensic examination and testimony.

Bias refers to systematic influence on interpretation or decision making arising from contextual information, cognitive processes, or external pressures.

Explain the necessity of limiting technical jargon when addressing the jury.

Limiting jargon ensures comprehension, avoids miscommunication, and maintains clarity of scientific concepts.

Summarize the central issue addressed in Smith v Arizona.

Smith v Arizona examined whether an analyst other than the original examiner may testify to analytical results without violating the Confrontation Clause.

State the obligations imposed by Brady and Giglio on forensic experts.

Brady requires disclosure of evidence favorable to the defendant. Giglio requires disclosure of information that may impeach a witness’s credibility, including prior misconduct or errors.

Define admissibility of evidence within the judicial system.

Admissibility refers to the determination that evidence meets legal standards of relevance and competence and may therefore be presented to the trier of fact.

Define materiality.

Materiality refers to whether evidence is directly related to facts at issue in the current case.

Define probativeness.

Probativeness refers to the degree to which evidence tends to make a fact more or less likely.

Identify four categories of competence limitations in evidence admissibility.

Competence may be limited by prejudice, constitutional constraints, statutory privileges, or hearsay restrictions.

State why hearsay is generally inadmissible in court.

Hearsay is excluded because it is an out of court statement offered to prove its truth without opportunity for cross examination of the declarant.

Explain how scientific evidence was evaluated prior to the Frye decision.

Scientific evidence was evaluated solely under the relevance standard without a requirement for general scientific acceptance.

State the central requirement of the Frye standard.

Frye requires that scientific methods be generally accepted by the relevant scientific community before being admitted as evidence.

Explain the function of peer review in scientific method validation.

Peer review evaluates methodology, detects errors, and supports reliability through expert scrutiny before publication.

State the three requirements of FRE 702 for admissibility of expert testimony.

Expert testimony must be based on sufficient facts, reliable principles and methods, and reliable application to the case.

Describe the judge’s role under the Daubert standard.

Under Daubert, the judge acts as gatekeeper to evaluate the scientific validity and reliability of proffered expert testimony.

Identify one Daubert criterion for evaluating scientific validity.

Falsifiability is a Daubert criterion.

Identify another Daubert criterion for evaluating scientific validity.

Known or potential error rates constitute a Daubert criterion.

Explain why epidemiological data were used in Daubert v Merrell Dow.

Epidemiological analysis was required because the biochemical mechanism for birth defects was unknown.

Define laboratory accreditation.

Accreditation is the formal evaluation of laboratory practices to ensure compliance with quality, reliability, and operational standards.

Define certification of forensic professionals.

Certification is an individual credential demonstrating competence through examination, proficiency testing, and professional evaluation.

State why forensic laboratory reports are considered hearsay.

Reports are hearsay because they are generated outside court by analysts who were not under oath at the time of writing.

Distinguish between Past Recollection Refreshed and Past Recollection Recorded.

Past Recollection Refreshed allows testimony after memory is restored by reviewing notes. Past Recollection Recorded permits the written report to serve as evidence when memory cannot be restored.

Define an expert witness under FRE 702.

An expert witness is an individual qualified by knowledge, skill, experience, training, or education to offer specialized opinions.

Explain the purpose of hypothetical questions in expert testimony.

Hypothetical questions permit experts to interpret evidence based on assumed facts without directly stating conclusions about the case.

Describe the Brandon Mayfield fingerprint case as it relates to bias.

The case demonstrates confirmational bias in which multiple examiners reproduced an erroneous conclusion due to awareness of prior determinations.

Define cognitive bias as shown in Dror’s fingerprint study.

Cognitive bias arises when contextual case information alters an examiner’s interpretation of evidence.

State why double blind procedures are used in scientific testing.

They prevent both participant and examiner from knowing conditions, thereby minimizing bias.

Define an expert witness and state the criteria by which an individual is qualified to provide expert testimony in forensic science.

An expert witness possesses specialized knowledge, training, education, or experience that enables interpretation of scientific or technical information beyond the understanding of a layperson.

State the purpose of expert testimony within the judicial process.

Expert testimony assists the trier of fact in understanding scientific principles, interpreting analytical results, and evaluating technical matters relevant to the case.

Describe the primary objectives of direct examination in forensic testimony.

Direct examination establishes the expert’s qualifications and elicits a clear explanation of analytical procedures, results, and conclusions.

Identify the central goal of cross examination in forensic science testimony.

Cross examination seeks to evaluate the reliability of the expert’s methods, challenge the expert’s conclusions, probe for inconsistencies, and assess potential bias.

Explain the professional rationale for conservative courtroom attire for forensic experts.

Conservative attire minimizes distraction, maintains credibility, and promotes focus on scientific testimony rather than personal appearance.

Define a subpoena duces tecum and specify its relevance to forensic testimony.

A subpoena duces tecum compels the expert to appear in court and produce all scientific records, including notes, reports, chain of custody documents, and supporting data.

Outline the essential components of pre testimony preparation for forensic scientists.

Preparation requires review of case notes, analytical data, laboratory procedures, chain of custody documentation, and personal qualifications.

State the legal function of the oath administered prior to testimony.

The oath binds the witness to provide truthful, complete, and accurate testimony under penalty of perjury.

Define voir dire in the context of expert witness qualification.

Voir dire is the process in which opposing counsel evaluates the expert’s qualifications before the judge determines admissibility of expert testimony.

Explain the importance of establishing chain of custody during testimony.

Chain of custody verifies the identity, integrity, and continuity of evidence from collection to analysis, ensuring admissibility and reliability.

Describe the nature of scientific challenges that may arise during cross examination.

Challenges may concern method validation, instrument reliability, error rates, analytical uncertainty, or interpretive limitations.

Define bias in the context of forensic examination and testimony.

Bias refers to systematic influence on interpretation or decision making arising from contextual information, cognitive processes, or external pressures.

Explain the necessity of limiting technical jargon when addressing the jury.

Limiting jargon ensures comprehension, avoids miscommunication, and maintains clarity of scientific concepts.

Summarize the central issue addressed in Smith v Arizona.

Smith v Arizona examined whether an analyst other than the original examiner may testify to analytical results without violating the Confrontation Clause.

State the obligations imposed by Brady and Giglio on forensic experts.

Brady requires disclosure of evidence favorable to the defendant. Giglio requires disclosure of information that may impeach a witness’s credibility, including prior misconduct or errors.

Define admissibility of evidence within the judicial system.

Admissibility refers to the determination that evidence meets legal standards of relevance and competence and may therefore be presented to the trier of fact.

Define materiality.

Materiality refers to whether evidence is directly related to facts at issue in the current case.

Define probativeness.

Probativeness refers to the degree to which evidence tends to make a fact more or less likely.

Identify four categories of competence limitations in evidence admissibility.

Competence may be limited by prejudice, constitutional constraints, statutory privileges, or hearsay restrictions.

State why hearsay is generally inadmissible in court.

Hearsay is excluded because it is an out of court statement offered to prove its truth without opportunity for cross examination of the declarant.

Explain how scientific evidence was evaluated prior to the Frye decision.

Scientific evidence was evaluated solely under the relevance standard without a requirement for general scientific acceptance.

State the central requirement of the Frye standard.

Frye requires that scientific methods be generally accepted by the relevant scientific community before being admitted as evidence.

Explain the function of peer review in scientific method validation.

Peer review evaluates methodology, detects errors, and supports reliability through expert scrutiny before publication.

State the three requirements of FRE 702 for admissibility of expert testimony.

Expert testimony must be based on sufficient facts, reliable principles and methods, and reliable application to the case.

Describe the judge’s role under the Daubert standard.

Under Daubert, the judge acts as gatekeeper to evaluate the scientific validity and reliability of proffered expert testimony.

Identify one Daubert criterion for evaluating scientific validity.

Falsifiability is a Daubert criterion.

Identify another Daubert criterion for evaluating scientific validity.

Known or potential error rates constitute a Daubert criterion.

Explain why epidemiological data were used in Daubert v Merrell Dow.

Epidemiological analysis was required because the biochemical mechanism for birth defects was unknown.

Define laboratory accreditation.

Accreditation is the formal evaluation of laboratory practices to ensure compliance with quality, reliability, and operational standards.

Define certification of forensic professionals.

Certification is an individual credential demonstrating competence through examination, proficiency testing, and professional evaluation.

State why forensic laboratory reports are considered hearsay.

Reports are hearsay because they are generated outside court by analysts who were not under oath at the time of writing.

Distinguish between Past Recollection Refreshed and Past Recollection Recorded.

Past Recollection Refreshed allows testimony after memory is restored by reviewing notes. Past Recollection Recorded permits the written report to serve as evidence when memory cannot be restored.

Define an expert witness under FRE 702.

An expert witness is an individual qualified by knowledge, skill, experience, training, or education to offer specialized opinions.

Explain the purpose of hypothetical questions in expert testimony.

Hypothetical questions permit experts to interpret evidence based on assumed facts without directly stating conclusions about the case.

Describe the Brandon Mayfield fingerprint case as it relates to bias.

The case demonstrates confirmational bias in which multiple examiners reproduced an erroneous conclusion due to awareness of prior determinations.

Define cognitive bias as shown in Dror’s fingerprint study.

Cognitive bias arises when contextual case information alters an examiner’s interpretation of evidence.

State why double blind procedures are used in scientific testing.

They prevent both participant and examiner from knowing conditions, thereby minimizing bias.

Q: Who is referred to as the "trier of fact" in the judicial process?

A: The "trier of fact" is the judge in a bench trial or the jury in a jury trial, responsible for determining the facts of a case.

Q: What does the Confrontation Clause within the U.S. Constitution guarantee?

A: The Confrontation Clause, found in the Sixth Amendment, guarantees a criminal defendant the right to confront, or cross-examine, witnesses against them.

Q: Identify an additional Daubert criterion for evaluating scientific validity, beyond falsifiability and error rates.

A: Whether the technique has been subjected to peer review and publication is another Daubert criterion.

Q: What Daubert criterion focuses on the consistency and control of a scientific technique's application?

A: The existence and maintenance of standards controlling the technique's operation, and whether those standards are followed, is a Daubert criterion.

Q: Distinguish between a "fact witness" and an "expert witness" in a legal proceeding.

A: A fact witness testifies to what they observed or personally experienced, while an expert witness provides opinions based on specialized knowledge and training.

Q: Explain the ethical obligations of a forensic scientist when providing courtroom testimony.

A: Forensic scientists are ethically obligated to present findings objectively, truthfully, and without bias, adhering to scientific principles and professional standards.

Q: What impact did the Supreme Court case of Melendez-Diaz v. Massachusetts have on the use of forensic laboratory reports in court?

A: Melendez-Diaz v. Massachusetts held that forensic laboratory reports are testimonial in nature and, under the Confrontation Clause, the analysts who prepared them must be available for cross-examination.

Q: What is meant by the "relevant scientific community" in the context of the Frye standard?

A: The "relevant scientific community" refers to a particular discipline or field of science whose practitioners would be familiar with the theory or technique in question and are in a position to assess its acceptance.

Q: Differentiate between scientific validity and scientific reliability as they pertain to forensic methods.

A: Scientific validity refers to whether a method measures what it claims to measure (accuracy), while scientific reliability refers to whether a method consistently produces the same results under the same conditions (precision).