Week 1 Incidence

Question 1

What is cumulative incidence?

Answer 1

Number of new cases/number of people at risk in a specific period of time

Question 2

What assumption does cumulative incidence (CI) make?

Answer 2

That the entire population at risk at the beginning of the study period has been followed up over the specified time period

Question 3

What can’t you use cumulative incidence over long periods of time?

Answer 3

1) it doesn’t account for competing risks (people removed from study due to death
2) It doesn’t take into account those lost to follow up

Question 4

What is incidence rate?

Answer 4

Number of new cases of a disease in a specific time period/ total person-time at risk during the time period

Question 5

What is the benefit of incidence rate over cumulative incidence

Answer 5

Allows account for variation in time at risk
(accounts for those who died or lost to follow up)

Question 6

What is the prevalent pot formula?

Answer 6

Prevalence (approx) = incidence x duration

Question 6

What is the prevalent pot formula?

Answer 6

Prevalence (approx) = incidence x duration

Question 6

What is the prevalent pot formula?

Answer 6

Prevalence (approx) = incidence x duration

Question 7

What is the prevalent pot formula?

Answer 7

Prevalence (approx) = incidence x duration

Question 8

What can you use the ‘prevalence pot’ formula to calculate incidence?

Answer 8

When the prevalence is < 10%

Question 9

What formula do you use to calculate incidence when the population is > 10%

Answer 9

Prevalence = Duration x incidence/ ([ 1+ (duration x incidence0]

Question 10

How is incidence information useful to reasearches?

Answer 10

It gives a risk of developing a disease