title: Deviation of a single observation from the hypothetical true value. Guidelines for computing the magnitude of misclassification of risk individuals due to this deviation.
abstract: In clinical work as well as in intervention studies, decisions concerning further follow-up or treatment of individuals are often based on a single measurement of each variable considered. If the measured variable for a certain individual varies considerably with time due to biological intra-individual variation and methodological variation, we would intuitively be sceptical to such decisions. The intra-individual variations, i.e. a composition of both biological and methodological variations, could be regarded as noise in the measurements. A more precise definition of noise would be: 'Noise is defined as random variations from a person's true value (hypothetical) in a time interval for which the true value is assumed constant.' Methodological variation, in particular, will sometimes lead to misclassifications (with respect to a given cut-off point) of a single measurement versus a person's true value. In this paper we will present formulas and tables which will help the reader to quantify such misclassifications in his/her own material.
authors.affiliation: Veritec A/S, Høvik, Norway.
authors.forename: E
authors.initials: E
authors.lastname: Funnemark
authors.forename: S
authors.initials: S
authors.lastname: Tretli
mesh_terms: D000328:Adult; D002318:Cardiovascular Diseases / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D003201:Computers; D003657:Decision Making; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D009664:Norway; D012307:Risk Factors