Cohort and Case Control

Question 1

What is a cohort study?

Answer 1

This is where you have two groups, either exposed or not and work forward.

This can be prospective or retrospective

Question 2

What is a case control study?

Answer 2

This is where you work with a disease or an outcome and work backwards

Question 3

Which one has a higher validity?

Answer 3

Cohort

Question 4

What are the advantages of a cohort study?

Answer 4

Good for rare exposures

Good for incidence

Less bias

Question 5

What are the disadvantages of a cohort study?

Answer 5

It is expensive

Question 6

What are the advantages of a case control study?

Answer 6

Good for rare diseases

Cheaper

Question 7

What are the disadvantages of a case control study?

Answer 7

Bias

Question 8

Which ones allows you work out risk and how do you do this?

Answer 8

Cohort study

Absolute risk = (Cases/total)

Relative risk = Absolute risk of group A/Absolute risk of group B

Attributable risk - Absolute risk A - Absolute risk B

SEE HANDOUT

Question 9

Which one allows you to work out the odds ratio and how?

Answer 9

Case control

(Cases who Have disease/dont have)

Divided by

(controls who have disease/dont have)

A VALUE BIGGER THAN 1 MEANS THE EXPOSURE IS ASSOCIATED WITH THE OUTCOME

This gives you a ratio. If this has a small P value and the confidence interval doesnt cross 1, it is significant

Question 10

What would the null hypothesis be for relative risk?

Answer 10

1

Question 11

What would the null hypotheses be for attributable risk?

Answer 11

0

Question 12

What is absolute risk the same as?

Answer 12

Incidence