OnlineMedEd: Epidemiology and Stats - "Bias"

Question 1

What is the Hawthorne effect?

Answer 1

People change their behavior when they know they are being observed.

(Imagine how Hester Prynn changed her behavior when everyone was watching her in Hawthorne’ Scarlet Letter.)

Question 2

Review the types of bias grouped by subjects, researchers, and the study type.

Answer 2

Subjects:

• Hawthorne effect: people act differently when observed
• Recall bias: people remember more when they’re sick

Researchers:

• Selection bias: groups are different at baseline
• Observer bias: researcher assesses groups differently when he/she knows which group they’re in

Study:

• Confounding: study didn’t account for third, hidden variable that influences study variables
• Effect modification:

Question 3

___________ bias means that the study groups were different at baseline.

Answer 3

Selection

Question 4

How is effect modification different from confounding?

Answer 4

Confounding negates the relationship between two variables because it accounts for both.

Effect modification enhances the relationship between the two variables.