Lead time bias

Lead time bias is a phenomenon that occurs in medical research and public health when evaluating the effectiveness of screening tests or early detection methods. It refers to the apparent prolongation of survival time due to the earlier diagnosis of a disease, rather than a true extension of life. Here's how it works: 1. **Early Detection**: When a disease like cancer is detected earlier through screening, patients often have a longer time between diagnosis and death, simply because the diagnosis is made sooner.