what is the difference between lead time and length time bias ?
Lead time bias is when a new screening test is developed and it catches the diseases earlier than prior techniques (mammography than physical exam for breast cancers)
While length time bias is when a technique catches ONLY THE SLOWLY PROGRESSIVE FORMS of diseases because the rapidly progressive forms are rapid and patients die so they go unnoticed. The study falsely shows that disease related mortality rate or complications are low, when in fact it’s fairly high.
Hope that helps.
Thank you so much for cleaning that concept