Bias due to wrong interpretation of laboratory test results in inter-observer variation is
Ans. c (Observation bias). (Ref. Park, PSM 22th/ pg. 70, 80)BIAS (SYSTEMATIC ERROR)A nonrandom error in a study that leads to a distorted result.Confounding biasA systematic error in a study that arises from mixing of the effect of the exposure of interest with other associated correlation of the disease outcome.Memory or Recall biasA systematic distortion of retrospective studies that can be eliminated by prospective design.E.g. Framington heart study.0Selection biasA systematic error in a study that arises from the manner in which subjects are sampled.Berkesonian biasArises because of the different rates of admission to hospitals for people with different disease Q.Lead-time biasApparent increase in the length of survival with a disease as a result of earlier recognition of the disease through the use of a screening procedure.Information/observation biasA systematic error in a study that arises from the manner in which data are collected from participants.Misclassification biasIncorrect characterization of the status subjects with regard to a study variable that leads to a distorted conclusion.Observers biasThe investigator measuring the outcome of a therapeutic trial may be influenced if he knows beforehand the particular procedure or therapy to which the patient has been subjected.Interviewer's biasOccurs when interviewer knows the hypothesis and also knows who the cases are. This may lead him to question the cases more thoroughly than controls. A useful check on this kind of bias can be made by noting the length of time taken to interview the avg case and the control case. This type of bias can be eliminated by double-blinding. Type of Bias in Research and important AssociationsType of BiasDefinitionimportant AssociationsSolutionsSelectionSample not representativeBerkesorin bias, non- respondent biasRandom, independent sampleMeasurementThe process of gathering information distorts itHawthorne effectControl group/placebo groupExperimenter expectancyResearcher's beliefs affect outcomePygmalion effectDouble-blind designLead timeEarly detection confused with increased survivalBenefits of screeningMeasure "Back end" survivalRecallSubjects cannot remember accuratelyRetrospective studiesMultiple sources to confirm informationLate-lookSeverely diseased individuals are not uncoveredEarly mortalitystratify by severityConfoundingUnanticipated factors obscure resultsHidden factors affect resultsMultiple studies, good research design
Selection bias
Sampling bias
Observation bias
Recall bias
Epidemiology