Systematic errors in etiological epidemiological studies
Journal Title: Αρχεία Ελληνικής Ιατρικής - Year 2005, Vol 22, Issue 2
Abstract
Measurement error refers to deviations between the estimated and the true value of a (biological) variable, which are not caused by mistakes. In epidemiological studies, errors are classified into random and systematic and the three categories of systematic error are selection bias, information bias and confounding. Selection biases result from procedures used to select the study population and from factors that influence study participation or participation in a specific group of the study. In cohort studies, these errors occur when participation is associated with the outcome under study and in case-control studies when participation is associated with the determinant. Information biases are introduced in a study when collected information regarding the category of the determinant, the outcome, or both is distorted. When the characteristic under study is qualitative and error leads some persons to be included in a wrong category, the bias is a misclassification. Finally, confounders are the external determinants of the frequency of the disease that are associated with the determinant under study and are not intermediate steps in the causal mechanism between the determinant and the disease. As opposed to selection and information biases, confounders can be controlled during both study design and data analysis.
Authors and Affiliations
K. MELLOU, L. SPAROS
Keywords
Related Articles
- EP ID EP159905
- DOI -
- Views 59
- Downloads 0
Tyrosine kinase inhibitor –<br /> a new targeted therapy for chronic myeloid leukemia
The treatment of patients with Ph(+) or BCR-ABL(+) chronic myeloid leukemia (CML) did not improve very greatly in the 1990s. It is now widely accepted that patients treated by allogeneic stem cell transplantation may be...
Chemoprevention of colorectal cancer
Colorectal cancer is among the leading causes of cancer-related deaths. Surgical resection combined with the use of evolving chemotherapeutic agents remains the only curative treatment, and the likelihood of cure is gr...
Assessing quality of care in Greek patients with inflammatory bowel disease <br /> <br />
OBJECTIVE Due to the chronic and recurrent nature of their disease and their normal life expectancy, patients with inflammatory bowel disease (IBD) may need considerable health care. Health care systems should therefore...
Mechanisms of the complications of diabetes: Newer aspects
Hyperglycemia is the basic metabolic disturbance in patients with diabetes. The chronic complications of the disease are associated with both the duration and the degree of hyperglycemia. At the cellular level, increased...
The adventurous discovery of Yersinia pestis as an example of personal conflicts and scientific controversies
The adventurous discovery of the bacterium of bubonic plague (Yersinia pestis), by Alexandre Yersin and Shibasaburo Kitasato during the third pandemic in Hong-Kong (1894) is presented. The two young scientists met at the...