Bias. Issue 8 (13th July 2004)

• Record Type: Journal Article
• Authors: Delgado-Rodríguez, M; Llorca, J
• Is Part Of: Journal of epidemiology and community health. Volume 58:Issue 8(2004)
• Page Start: 635
• Page End: 641
• Publication Date: 2004-07-13
• Subjects: bias -- selection bias -- information bias -- confounding; Public health -- Periodicals; Epidemiology -- Periodicals; 614.4
• DOI: 10.1136/jech.2003.008466
• Languages: English
• ISSNs: 0143-005X

Abstract

Abstract : The concept of bias is the lack of internal validity or incorrect assessment of the association between an exposure and an effect in the target population in which the statistic estimated has an expectation that does not equal the true value. Biases can be classified by the research stage in which they occur or by the direction of change in a estimate. The most important biases are those produced in the definition and selection of the study population, data collection, and the association between different determinants of an effect in the population. A definition of the most common biases occurring in these stages is given.