Lead Time Bias

Lead time bias is the bias that occurs when two tests for a disease are compared, and one test (the new, experimental one) diagnoses the disease earlier, but there is no effect on the outcome of the disease—it may appear that the test prolonged survival, when in fact it only resulted in earlier diagnosis when compared to traditional methods. It is an important factor when evaluating the effectiveness of a specific test.

Read more about Lead Time BiasRelationship Between Screening and Survival

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Screening (medicine) - Analysis of Screening - Lead Time Bias
... For more details on this topic, see Lead time bias ... cases a person will die at the same time, because we diagnosed the disease earlier with screening the survival time since diagnosis is longer with screening but life span has not been ... Looking at statistics of survival time since diagnosis, screening will show an increase (this gain is called lead time) ...
Lead Time Bias - Relationship Between Screening and Survival
... Even if in both cases a person will die at the same time, because the disease was diagnosed early with screening, the survival time since diagnosis is longer with ... Looking at raw statistics, screening will appear to increase survival time (this gain is called lead time) ... If we do not think about what survival time actually means in this context, we might attribute success to a screening test that does nothing but advance diagnosis ...

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