L2: Study design part 3

Question 1

potential errors and biases in observational studies?

Answer 1

Selection bias
Study population differs from broader population in terms of the relationship between exposure and outcome

Measurement (information) bias
Measurement of exposure or outcome differs between groups

Confounding:
Other factors associated with both exposure and outcome can distort the main effect if not taken into account

Random error:
Due to natural variation in the population / less precise measurements
Validity of study findings:
Internal validity
are findings of the study correct?
depends on study design and appropriate analysis.

External validity
are the findings generalizable to the broader population?
depends on study sample & setting.

Look at the summaries and examples at the end of the powerpoint