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.
Evidence Search Dog
A canine trained to locate and indicate items in question by means of detecting a trained odor/ human scent.
evidentiary data
Data generated from an evidentiary sample and not from a reference sample.
Evidentiary Data
Data derived from biological specimens of unknown source.
evidentiary sample
Biological sample recovered from a crime scene or collected from persons or objects associated with a crime.
examination
part of the forensic process consisting of the recovery and analysis of items, and the interpretation of observations obtained from the analysis of items
Note 1 to entry: See Annex A for a flowchart of the forensic process.
examination
The process of observing, searching, detecting, recording, prioritizing, collecting, analyzing, measuring, comparing, and/or interpreting.
examination
The process of observing, searching, detecting, recording, prioritizing, collecting, analyzing, measuring, comparing, and/or interpreting.
examination (modified)
part of the forensic toxicology process consisting of the analysis of specimen(s) and the interpretation of observations from the analysis
Examination Quality Photograph
A photograph that is scalable and captures a sufficient level of detail for conducting a forensic footwear or tire examination.
examination strategy
choice of method(s) and sequence of methods for the examination
Note 1 to entry: An examination strategy is based in part on relevant case questions and background information.
Note 2 to entry: An examination strategy can be applied to the examination of a scene, the examination of items or sequential multi-discipline examination of items.
Examiner
examiner (friction ridge, competent friction ridge examiner
An individual authorized to conduct independent friction ridge examinations for the forensic service provider by observing and interpreting data, making decisions, forming conclusions and opinions, issuing reports and/or providing testimony. Use of the term “examiner” in this document refers to a “competent friction ridge examiner” and not a “trainee.”
Examiner (friction ridge)
An individual authorized to conduct independent friction ridge examinations for the forensic service provider by observing and interpreting data, making decisions, forming conclusions and opinions, issuing reports and/or providing testimony. Use of the term “examiner” in these documents refers to a “competent friction ridge examiner” and not a “trainee.”
examiner (friction ridge)
An individual who has successfully completed their FSP’s training program, and is authorized to conduct independent friction ridge examinations for the FSP by observing and interpreting data, making decisions, forming conclusions and opinions, issuing reports, and/or providing testimony.
NOTE Use of the term “examiner” in these documents refers to a “friction ridge examiner” and not a “trainee.”
examiner (friction ridge)
An individual authorized to conduct independent friction ridge examinations for the FSP by observing and interpreting data, making decisions, forming conclusions and opinions, issuing reports and/or providing testimony. Use of the phrase examiner in these documents refers to a “competent friction ridge examiner” and not a “trainee.”
examiner (friction ridge) ‐ (compare to trainee)
An individual who has successfully completed their FSP’s training program, and is authorized to conduct independent friction ridge examinations for the FSP by observing and interpreting data, making decisions, forming conclusions and opinions, issuing reports and/or providing testimony. Use of the term “examiner” in these documents refers to a “friction ridge examiner” and not a “trainee,” refer to those definitions for further clarification.
examiner (friction ridge) – (compare to trainee)
An individual who has successfully completed their FSP’s training program, and is authorized to conduct independent friction ridge examinations for the FSP by observing and interpreting data, making decisions, forming conclusions and opinions, issuing reports and/or providing testimony. Use of the term “examiner” in these documents refers to a “friction ridge examiner” and not a “trainee.” Refer to those definitions for further clarification.
examiner (friction ridge) (compare to competent friction ridge examiner)
An individual authorized to conduct independent friction ridge examinations for the forensic service provider by observing and interpreting data, making decisions, forming conclusions and opinions, issuing reports and/or providing testimony. Use of the term “examiner” in these documents refers to a “competent friction ridge examiner” and not a “trainee.”
Exchange Schema
Although NIEM contains thousands of elements it does not contain everything needed inan XML exchange. It contains the most common building blocks. In addition,implementers can define, in other exchange schemas, user-defined elements from theimplementers domain.
excitation
Elevation of the energy levels of atoms, molecules, or ions to higher energy levels. (CIE S 017/E:2011 ILV)
Excitation filter
exclusion
The known footwear or tire exhibits differences in class characteristics or distinguishing characteristics that indicate the footwear or tire did not make the questioned impression and thus is not part of the pool of potential sources for the questioned impression.
Exclusion
OSAC Preferred
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.
exclusion elimination
The determination that there are sufficient characteristics in disagreement, with no significant limitations, to support an opinion that two or more items did not originate from the same source.
Exclusion Scent Check
A type of location search in which a scent match is not indicated by the canine thereby excluding an individual as the scent contributor.
Exclusion with Limitations
exclusion, exclusionary conclusion
A conclusion that eliminates an individual as a contributor of DNA obtained from an evidentiary sample based on the comparison of DNA data.
Exclusion/Elimination
exclusionary difference
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.
NOTE What is sufficient depends on the performance and limitations of the method used on the material in question.
Exclusionary Difference
OSAC Preferred
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.
Also referenced in ANSI/ASTM E1732 Standard Terminology Relating to Forensic Science
ANSI/ASTM E1732 Discussion—What is sufficient depends on the performance and limitations of the method used on the material in question.
exculpatory evidence
Evidence that may be favorable to the accused, impeach the prosecution’s evidence, or mitigate the offense.
Exemplar
Exemplar
Exemplar
The friction ridge prints of an individual, associated with a known or claimed identity,and deliberately recorded electronically, by ink, or by another medium (also called 'known prints').
exemplar impression (synonym of exemplar or known and exemplar prints) exemplar or known (synonym of exemplar impression and exemplar prints) exemplar prints (synonym of exemplar impression and exemplar or known)
The deliberately recorded images or impressions from the friction ridge skin of an individual.
NOTE Examples may include inked tenprints, inked palm prints, Livescan prints, powder and lift prints, casted/molded prints, or photographs of friction ridge skin.
exemplar impression exemplar or known exemplar prints
The deliberately recorded images or impressions from the friction ridge skin of an individual.
NOTE Examples may include, but are not limited to, inked tenprints, inked palm prints, Livescan prints, powder and lift prints, casted/molded prints, or photographs of friction ridge skin.
exemplar impression, exemplar or known exemplar prints
The deliberately recorded images or impressions from the friction ridge skin of an individual. NOTE Examples may include, but are not limited to, inked tenprints, inked palm prints, Livescan prints, powder and lift prints, casted/moulded prints, or photographs of friction ridge skin.
exemplar impression, exemplar or known exemplar prints
The deliberately recorded images or impressions from the friction ridge skin of an individual. NOTE Examples may include, but are not limited to, inked tenprints, inked palm prints, Livescan prints, powder and lift prints, casted/moulded prints, or photographs of friction ridge skin.
exemplar impression, exemplar or known exemplar prints
The deliberately recorded images or impressions from the friction ridge skin of an individual.
NOTE Examples may include, but are not limited to, inked tenprints, inked palm prints, Livescan prints, powder and lift prints, casted/moulded prints, or photographs of friction ridge skin.
exemplar prints
The deliberate recorded images or impressions from the friction ridge skin of an individual.
exemplars
Samples of handwriting, printed text, paper, ink, etc., known (or purported) to have been produced by a particular individual, machine, or manufacturer.
exemplars
Samples of handwriting, printed text, paper, ink, etc., known (or purported) to have been produced by a particular individual, machine, or manufacturer.
exigent circumstances
Circumstances that would cause a reasonable person to believe that relevant prompt action was necessary to prevent physical harm to persons or animals, the destruction of relevant evidence or some other consequence improperly frustrating legitimate law enforcement efforts.
Expanded Uncertainty (U)
Quantity defining an interval about a result of a measurement that may be expected to encompass a large fraction of the distribution of values that could reasonably be attributed to the measurand. DISCUSSION(1) The fraction may be regarded as the coverage probability or level of confidence of the interval. (2) To associate a specific level of confidence with the interval defined by the expanded uncertainty requires explicit or implicit assumptions regarding the probability distribution characterized by the measurement result and its combined standard uncertainty. The level of confidence that may be attributed to this interval can be known only to the extent to which such assumptions can be justified. (3) An expanded uncertainty U is calculated from a combined standard uncertainty uc and coverage factor k using: U =k X uc.
Expanded Uncertainty, U
expectation value (e-value)
The number of distinct alignments expected by chance; the default sorting metric in BLAST search results.
Experimental Bias
Anyone testing any idea has a strong expectation that leads to an influence about the outcome.
Expert
A person displaying special skill and knowledge in a given area derived from training, education, or experience.
expert system
A software program or set of software programs that interprets the data generated from a DNA analysis instrument platform in accordance with laboratory defined quality assurance rules and accurately identifies the data that does and does not satisfy such rules.
Expert Testimony
The testimony made by a qualified person about a scientific, technical, or professional issue. An expert is often called upon to testify due to his/her familiarity with the subject or special training in the field.