Advanced
Technical
IVT
length time bias
Screening bias where slow-growing tumors are disproportionately detected, creating apparent survival benefit.
Full Definition
Length time bias occurs when screening programs preferentially detect slow-growing, less aggressive cancers that have longer preclinical phases, while fast-growing aggressive cancers are more likely to present symptomatically between screening rounds. This creates an apparent improvement in survival outcomes that may not reflect true screening benefit, as screen-detected cancers naturally have better prognoses regardless of early detection. Understanding this bias is crucial for accurate interpretation of screening program effectiveness.
Usage
Usage note: Often confused with lead time bias; specify which bias is being discussed.
In Context
- "The survival benefit may be partially explained by length time bias favoring indolent tumors." — Research discussion
- "Investigators controlled for length time bias by examining cancer-specific mortality rather than survival." — Methodology section
Also known as
length bias
Don't confuse with
lead time bias
overdiagnosis