[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Epidemiology](https://durgical.com/en/epidemiology/) › Screening

# Screening

What makes a good screening programme and its biases: lead time, length and overdiagnosis.

5 pages

## Measure

- [**Evaluating a screening programme** A screening programme is judged by how many people it reaches, what it finds and, above all…](https://durgical.com/en/epidemiology/evaluating-a-screening-programme/)

## Bias

- [**Lead-time bias** Screening moves the date of diagnosis earlier; survival looks longer even if the person dies on…](https://durgical.com/en/epidemiology/lead-time-bias/)
- [**Length-time bias** Screening mostly finds slow cases, which spend longer without symptoms and already had a better…](https://durgical.com/en/epidemiology/length-time-bias/)
- [**Overdiagnosis** Overdiagnosis is diagnosing a real disease that would never have caused symptoms or death in…](https://durgical.com/en/epidemiology/overdiagnosis/)

## Concept

- [**Principles of screening** Screening looks for disease in people without symptoms; it is worth it only if the benefit is…](https://durgical.com/en/epidemiology/principles-of-screening/)

## A to Z

- [A](https://durgical.com/en/epidemiology/a-z/a/)
- [B](https://durgical.com/en/epidemiology/a-z/b/)
- [C](https://durgical.com/en/epidemiology/a-z/c/)
- [D](https://durgical.com/en/epidemiology/a-z/d/)
- [E](https://durgical.com/en/epidemiology/a-z/e/)
- [F](https://durgical.com/en/epidemiology/a-z/f/)
- [G](https://durgical.com/en/epidemiology/a-z/g/)
- [H](https://durgical.com/en/epidemiology/a-z/h/)
- [I](https://durgical.com/en/epidemiology/a-z/i/)
- [K](https://durgical.com/en/epidemiology/a-z/k/)
- [L](https://durgical.com/en/epidemiology/a-z/l/)
- [M](https://durgical.com/en/epidemiology/a-z/m/)
- [N](https://durgical.com/en/epidemiology/a-z/n/)
- [O](https://durgical.com/en/epidemiology/a-z/o/)
- [P](https://durgical.com/en/epidemiology/a-z/p/)
- [Q](https://durgical.com/en/epidemiology/a-z/q/)
- [R](https://durgical.com/en/epidemiology/a-z/r/)
- [S](https://durgical.com/en/epidemiology/a-z/s/)
- [T](https://durgical.com/en/epidemiology/a-z/t/)
- [U](https://durgical.com/en/epidemiology/a-z/u/)
- [V](https://durgical.com/en/epidemiology/a-z/v/)
- [W](https://durgical.com/en/epidemiology/a-z/w/)
- [Y](https://durgical.com/en/epidemiology/a-z/y/)

[← Epidemiology, biostatistics and public health](https://durgical.com/en/epidemiology/)

Educational content on epidemiological and statistical methods; the examples use made-up numbers to teach the calculation. Not a clinical or legal guide: current Colombian rules are in the official sources.

Representative model, for educational purposes only.

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Source: https://durgical.com/en/epidemiology/areas/screening/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/epidemiology/areas/screening/