Week 141 - Measurements in populations II Flashcards Preview

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Flashcards in Week 141 - Measurements in populations II Deck (7):

What is chance?

The occurrence of an event based on probability


What is selection bias?

The selection of controls that are not representative of the population


What is information bias?

Recall bias
i.e. asking a person what they ate at a certain event
- people will recall information to a different accuracy


What is a confounding variable?

A variable that can cause or be associated with the disease and is also linked the the exposure of interest

i.e. a study between alcohol intake and IHD
- those who drink alcohol are more likely to smoke, and smoking has an association with IHD


What is residual confounding and how can this be dealth with?

When all confounding factors have been accounted for but there remain unknown confounders

Can be dealth with by randomisation


What is standardisation ad what types are there?

A technique used to remove the effects of differences in confounders (i.e. age) when comparing two or more populations

Two types:
- Indirect
- Direct


What is indirect standardisation?

Rate of a certain disease in a reference population is calculated then these raes are applied to the study population

If calculated rates < actual study rates => study population has a higher rate of disease