OSAC Lexicon
The OSAC Lexicon is a compendium of forensic science terms and definitions. This terminology tool was created to help bring consistency and understanding to the way terms are used by the various forensic science. Use of the OSAC Lexicon does not replace the need to reference the original published source.
The terms and definitions in the OSAC Lexicon come from the published literature, including documentary standards and technical reports. It is continually updated with the latest work from OSAC units, as well as terms from newly published documentary standards and standards elevated to the OSAC Registry.
Gradually terms are evaluated and harmonized by the OSAC to a single term. This process results in an OSAC Preferred Term. An OSAC Preferred Term is a term, along with its definition, that has undergone review and evaluation by the FSSB Terminology Task Group and has been approved by the FSSB. The FSSB recommends that subcommittees use OSAC Preferred Terms when drafting standards.
The OSAC Lexicon should be the primary resource for terminology and used when drafting and editing forensic science standards and other OSAC work products.
Process of assessing a level of confidence in identify or identification.
A tendency for an individual’s preexisting beliefs, expectations, motives, or the situational context to influence their sampling, observations, results, interpretations, or opinions, or their confidence in the aforementioned.
Also referenced in ANSI/ASB Standard 024 Standard for Training and Certification of Canine Detection of Humans: Location Check Using Pre‐scented Canines, ASB Technical Report 025 Crime Scene/Death Investigation – Dogs and Sensors – Terms and Definitions, ANSI/ASB Standard 024 Standard for Training and Certification of Canine Detection of Humans: Location Check Using Pre‐scented Canines, ANSI/ASB Standard 088 General Guidelines for Training, Certification, and Documentation of Canine Detection Disciplines, ANSI/ASB Standard 154 Standard for Training on Testimony for Forensic Biology
A tendency to search for, collect, perceive, or interpret information in a manner that supports preconceptions, expectations, or desires.
NOTE: This is a type of cognitive bias.
A tendency for exposure to or knowledge of case-specific information to affect the impartial collection, perception, or interpretation of evidence.
NOTE: This is a type of cognitive bias.
Also referenced in ASB Technical Report 025, Crime Scene/Death Investigation – Dogs and Sensors – Terms and Definitions
A systematic tendency for estimates or measurements to be above or below their true values.
NOTE 1: Statistical bias arises from systematic as opposed to random error.
NOTE 2: Statistical bias can occur in the absence of prejudice, partiality, or discriminatory intent.
Chronological record of the handling and storage of an item from its point of collection to its final return or disposal.
Also referenced in ANSI/ASB 019, Wildlife Forensics General Standards and ANSI/ASB Technical Report 025, Crime Scene/Death Investigation - Dogs and Sensors - Terms and Definitions
Evaluation of a persons knowledge and ability to perform work before authorization to do so independently.
Material of established origin used to evaluate the performance of a test or comparison. Or A test performed to demonstrate that a test method works correctly and to ensure that data are valid. Positive controls confirm that the procedure will produce the expected result. Negative controls confirm that the procedure does not produce an unintended result.
A result that compared items did not originate from the same source, are not the same substance, or do not share the same composition or classification, based on an exclusionary difference.
Also referenced in ASB 097, Terminology Used for Forensic Footwear and Tire Evidence.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
The application of scientific principles and techniques to matters of criminal justice especially as relating to the collection, examination, and analysis of physical evidence.
An organization or individual that provides forensic science services.
Also referenced in ANSI/ASB 017 Standard Practices for Measurement Traceability in Forensic Toxicology, ASTM E1732-24ae1 Standard Terminology Relating to Forensic Science, ANSI/ASTM E2917-24a Standard Practice for Forensic Science Practitioner Training, Continuing Education, and Professional Development Programs, ANSI/ASTM E3255-21 Standard Practice for Quality Assurance of Forensic Science Service Providers Performing Forensic Chemical Analysis, ANSI/ASB 142-22 Best Practice Recommendations for the Resolution of Conflicts in Friction Ridge Examination, ANSI/ASB Standard 157-23 Required Components for a Proficiency Testing Program in Bloodstain Pattern Analysis
Activities included in the collection, examination, and analysis of items and reporting of observations and opinions for matters of criminal justice, or for regulatory, or legal proceedings.
An organization or individual that provides forensic services.
Also referenced in ASB 145 Standard for Consultation During Friction Ridge Examination.
Organization, performance and evaluation of measurements or tests on the same or similar items by two or more laboratories in accordance with predetermined conditions.
Also referenced in ANSI/ASTM E3255-21 Standard Practice for Quality Assurance of Forensic Science Service Providers Performing Forensic Chemical Analysis.
Explanations for the observations, data, and calculations.
Also referenced in ANSI/ASB 040 Standard for Forensic DNA Interpretation and Comparison Protocols, ANSI/ASB 038 Standard for Internal Validation of Forensic DNA Analysis Methods.
Organization, performance and evaluation of measurements or tests on the same or similar items within the same laboratory in accordance with predetermined conditions.
Also reference in ANSI/ASTM E3255-21 Standard Practice for Quality Assurance of Forensic Science Service Providers Performing Forensic Chemical Analysis
Recognizing and noting an occurrence.
View, judgment, belief - takes into consideration other information in addition to observations, data, calculations, and interpretations.
An independent evaluation of a scientific, professional, or academic manuscript or publication by a qualified second party to evaluate the claims, methods, interpretations, and conclusions.
Also referenced in ANSI/ASB Technical Report 025, Crime Scene/Death Investigation - Dogs and Sensors - Terms and Definitions, ASTM E2916-13 Standard Terminology for Digital and Multimedia Evidence Examination.
The ongoing process of evaluating a forensic service providers ability to perform work. Examples include quality control measures, observation, case review, retesting, blind testing, testimony monitoring, intra- or interlaboratory comparisons, and proficiency testing.
evaluation of participant performance against pre-established criteria by means of interlaboratory comparisons.
Also referenced in ASTM E1732-24ae1 Standard Terminology Relating to Forensic Science, ANSI/ASTM E1301-95 Standard Guide for Proficiency Testing by Interlaboratory Comparisons, ANSI/ASB Standard 153 Standard Practices for Proficiency Testing for Forensic Toxicology Laboratories and Breath Alcohol Programs.
Credibility and trustworthiness of proffered evidence.
Consistency of results as demonstrated by reproducibility or repeatability.
Extent of agreement between more than one result determined in the same place, by the same person, on the same equipment, in the same way, at similar times.
Also referenced in ASTM E1732-24ae1 Standard Terminology Relating to Forensic Science, ASTM E177-14 Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods.
See "Reproducibility"
Extent of agreement between repeated results determined under any combination of different conditions.
Also referenced in ANSI/ASB Technical Report 025, Crime Scene/Death Investigation - Dogs and Sensors - Terms and Definitions, ASTM E1732-24ae1 Standard Terminology Relating to Forensic Science, ASTM E177-14 Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods.
The product of the forensic service provider. This term is broad and includes observations, data, calculations, interpretations, and opinions.
A qualified second party's evaluation of reports, notes, data, and other documentation to ensure there is appropriate and sufficient support for the actions, results, conclusions, opinions, and interpretations.
Also referenced in ANSI/ASB 019 Wildlife Forensics General Standards, ANSI/ASB Technical Report 025, Crime Scene/Death Investigation - Dogs and Sensors - Terms and Definitions, ANSI/ASB 063 Implementation of 3D Technologies in Forensic Firearm and Toolmark Comparison Laboratories, ANSI/ASB 142-22 Best Practice Recommendations for the Resolution of Conflicts in Friction Ridge Examination, ANSI/ASTM E3392-24 Standard Guide for Forensic Physical Fit Examination.
A process of evaluating a system, method, or component, to determine that requirements for an intended use or application have been fulfilled.
Also referenced in ANSI/ASB Technical Report 025, Crime Scene/Death Investigation - Dogs and Sensors - Terms and Definitions, ANSI/ASB 018 Standard for Validation of Probabilstic Genotyping Systems, ANSI/ASB 020 Standard for Validation Studies of DNA Mixtures, and Development and Verification of a Laboratory's Mixture Interpretation Protocol, ANSI/ASB 038 Standard for Internal Validation of Forensic DNA Analysis Methods, ANSI/ASB 019 Wildlife Forensics General Standards, ANSI/ASB 047 Wildlife Forensics Validation Standard and Validating New Primers for Sequencing, ANSI/ASB 022 Standard for Forensic DNA Analysis Training Programs, ANSI/ASB 063 Implementation of 3D Technologies in Forensic Firearm and Toolmark Comparison Laboratories, ASTM E1732-24ae1 Standard Terminology Relating to Forensic Science.
Performing subsequent testing to ascertain if the results are concordant.