Forensic Science Legal Standards and Evidence Comparison

Vocabulary flashcards covering legal foundations, courtroom procedures, standards organizations, and evidence comparison types in forensic science.

Confrontation Clause

A 6th Amendment constitutional right relevant to forensic testimony and evidence examination.

Crawford v. Washington (2004)

A Confrontation Clause case involving the admissibility of a tape recording.

Melendez-Diaz v. Massachusetts (2009)

A Supreme Court case ruling that forensic laboratory reports are testimonial under the Confrontation Clause.

Brady v. Maryland (1963)

A Supreme Court case establishing that the prosecution must disclose new, potentially exculpatory evidence.

United States v. Bagley (1985)

A case addressing prosecution disclosure duties, noted for evidence that "didn't say much."

Kyles v. Whitley (1995)

A Supreme Court ruling affirming that the prosecutor has an affirmative duty to disclose favorable evidence.

Federal Rules of Evidence (FRE) (1975)

Codified rules of evidence enacted in 1975 governing relevance, exceptions, exclusions, and expert testimony under Rule 702.

Rule 702

A Federal Rule of Evidence governing expert witnesses, serving as quality control of analysis and opinion.

National Academy of Sciences (NAS)

A scientific institution established in 1863.

OSAC (Organization of Scientific Area Committees)

An organization formed under NIST in 2014 to develop and strengthen forensic science consensus standards.

Examiners speaking for evidence

The role of forensic examiners to associate, exclude, or identify evidence.

American Bar Association

The organization that sets ethical rules and professional standards for attorneys in the US.

Adversarial System

A legal system used in the US, Canada, Australia, UK, Ireland, and New Zealand where the police work with the prosecutor's office and opposing sides present their cases.

Inquisitorial System

A legal system with no set criteria for admissibility, usually no objections, and where most testimony is submitted as a written report (which can also occur in adversarial systems if both sides stipulate).

Examining Magistrate

A judicial official in an inquisitorial system who is responsible for deciding what evidence is examined.

Brady Violation

Occurs when the prosecution fails to turn over evidence that could impeach a witness or favor the defense.

Certification

A professional credential awarded to an individual forensic practitioner.

Accreditation

A formal recognition awarded to an organization or laboratory demonstrating technical competence.

ASTM (American Society for Testing and Materials)

An organization founded in 1898 that develops voluntary consensus standards.

NIST (National Institute of Standards and Technology)

A federal agency founded in 1901 that promotes measurement science, standards, and technology.

ANSI (American National Standards Institute)

Founded in 1918; serves as the United States representative to the International Organization for Standardization (ISO).

ISO (International Organization for Standardization)

An international standard-setting body established in 1947; notable in forensics for standard ISO 21043.

ASCLD-LAB

American Society of Crime Laboratory Directors/Laboratory Accreditation Board, founded in 1973; merged with ANAB and bases standards on ISO 17025.

ANAB

ANSI National Accreditation Board, which merged with ASCLD-LAB.

NIJ / TWG

Technical Working Groups organized by the National Institute of Justice.

NIJ / SWG

Scientific Working Groups organized by the National Institute of Justice.

Court Trial Rates

$97\%$ of cases do not go to trial; only $2\%$ go to court overall, and $3\%$ in Ohio.

Identification (Comparison Type)

Matching an unknown substance against a known standard in a database (e.g., drug chemistry).

Comparison (Comparison Type)

Comparing material recovered from a crime scene with material from a known source (e.g., paint).

Classification (Comparison Type)

Comparing known evidence against a reference collection to determine class (e.g., deer hair).

Individualization (Comparison Type)

Demonstrating that an item from an unknown source originates from a single unique source (e.g., fingerprint).

Bayesian Approach

A probabilistic framework using likelihood ratios to update beliefs, calculated as: $\text{prior odds} \times \text{likelihood ratio} = \text{posterior odds}$.