Observational Bias in Statistical Analysis

Overview by Dr. Busti

Observational Bias in Statistical Analysis

Background

Observational bias is a common type of systematic error that occurs in studies where there is inaccurate:

Classification of disease
Measurement of disease
Exposure

Common Reasons for Observational Bias

Detection Bias:

Increased monitoring of a group of exposed patients due to a known risk factor compared to an unexposed group that leads to a higher probability of detecting the disease.

Observer Bias:

Misclassification of date because of differences in observer interpretation or expectations regarding the study.

Recall Bias:

Relies on the subject to remember certain information accurately.Subjects who have a negative outcome may be more likely to report certain exposures compared to subjects who had a positive outcome.

Reporter Bias:

The subject either over or under report exposures due to perceived social stigmatization or based on what that subject believes to be important.

Considerations

Recall bias is most commonly seen in retrospective studies.

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