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.
estimate of systematic measurement error, calculated as the difference between the mean of several measurements under identical conditions to a known “true” value. It is often reported as a percent difference.
Preconception; prejudice; taint; partiality. Since most persons have biases, the issue is whether the bias is such that impartiality cannot be achieved and a fair outcome cannot occur. Any predisposition that a judge or arbitrator may have may be grounds for recusal. Any predisposition that a witness may have may be grounds for impeachment by cross-examination. Any predisposition that a juror may have may be grounds for excusal determined by through a process known as voir dire. This use of the term 'bias' is not that as used in statistical evaluations. (See cognitive bias, contextual bias, and experimental bias.)
An estimate of systematic measurement error, calculated as the difference between the mean of several measurements under identical conditions, to a known true value. It is often reported as a percent difference
The variance of measured results as influenced by human perceptions or systemic factors. Note: It is beyond the scope of this document to outline the numerous types of biases
Estimate of systematic measurement error, calculated as the difference between the mean of several measurements under identical conditions to a known “true” value
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.
an anisotropic crystal in the orthorhombic, monoclinic, or triclinic system with three principal refractive index directions (α, β, γ) and two optic axes that are isotropic.
An allele designation corresponding to the window of fragments sizes for each allele, determined by empirical testing.
Allele designations corresponding to the window of fragment sizes for each allele, determined by empirical testing
The study of the geographical distribution of living things.
The age corresponding with the developmental, degenerative, biochemical or isotopic status of an individual. Note: The rate at which organ systems age may differ from the individual's chronologic age.
Any liquid biological specimen that is typically pipetted for analysis (e.g., blood, urine, bile, serum, vitreous humor, oral fluid)
The description of an individual’s estimated age, sex, population affinity, and stature derived from skeletal analysis.
The description of an individual’s estimated age, sex, ancestry/population affinity, and living stature derived from an anthropological (skeletal) analysis.
The description of an individual’s estimated sex, ancestry, age, and living stature derived from an anthropological (skeletal) analysis.
The description of an individual’s estimated age, sex, ancestry, and living stature derived from an anthropological (skeletal) analysis.
The description of an individual’s estimated age, sex, ancestry, and living stature derived from an anthropological (skeletal) analysis.
the numerical difference between the maximum and minimum refractive indices of anisotropic substances.
a control where a specified component(s) is not present. Discussion - - Blanks with various designations can be specified, such as system blank, process blank, method blank, reagent blank, solvent blank, etc. Certain blanks may also serve as a negative control.
Any area or container where target odor/scent is not present. (See blank search.)
A biological fluid or tissue (or synthetic substitute) without target analyte or internal standard
A training or certification exercise in which the target odor/scent is not present.
A training or certification exercise in which the target scent is not present.
A training or certification exercise in which the target scent is not present.
A training or certification exercise in which the target scent is not present.
A known odor/scent sample that is used to assess the canine's proficiency in a non-matching odor/scent scenario. The canine is expected to give a negative response.