NNS
Also written as: NNS — Number Needed to Screen
Number Needed to Screen, the number of people who must be screened to prevent one cancer death.
Full Definition
NNS (Number Needed to Screen) represents the number of individuals who must undergo screening to prevent one cancer-related death over a specified time period. This metric helps quantify screening program efficiency and enables comparison between different screening strategies or populations. Lower NNS values indicate more efficient screening, while higher values suggest greater resource requirements per life saved. NNS calculations must account for screening frequency, follow-up duration, and population characteristics.
Usage
Usage note: Always specify the time period and outcome (deaths prevented vs. cancers detected).
In Context
- "The NNS for mammography screening was estimated at 1,339 women over 10 years." — Cost-effectiveness analysis
- "Researchers calculated an NNS of 377 for high-risk individuals compared to 1,200 for average-risk populations." — Risk stratification study