Tag Archives: lead time bias

Keep an eye out for lead-time bias with COVID-19 deaths

Tara Haelle

About Tara Haelle

Tara Haelle (@TaraHaelle) is AHCJ's medical studies core topic leader, guiding journalists through the jargon-filled shorthand of science and research and enabling them to translate the evidence into accurate information.

patient in hospital bed

Photo: Andrea Piacquadio from Pexels

Lead time bias is a well-recognized challenge especially when it comes to studies and statistics looking at cancer screenings. As the entry on the AHCJ website explains, lead time bias is a type of bias that can “artificially inflate the survival time of someone with a disease.”

How? When providers get better at looking for — and finding — a disease, it appears to lengthen the time someone survives after diagnosis. In reality, the patient is not necessarily living longer than they would have if the disease were discovered later. It just seems like they’re living longer because the disease is identified sooner, and the “clock” on survival time starts earlier. Continue reading