Epiville

Interactive

Cohort Study: SIR Step 3

SIR Step 3

Calculate the expected number of cases given the incidence rate in your reference population. How does one calculate the expected number of cases?

  1. the person-time accumulated in our study group
  2. the total number of cases observed, and
  3. the incidence rate of neurological disorders in the general population.

[Hint: Keep in mind the definition of an incidence rate (# Cases/Person-time of Observation)].
Expected Cases = (Person-time accumulated in our study group) * (The incidence rate of neurological disorders in the general population)

SUPERCLEAN Employees
Epiville
Age (Yrs) (1) N (Person-Time) (2) Observed Cases (3) Incidence Rate Per PYO' s (4) Expected Cases (2*4)
20-25 5114 47 0.00039
25-30 6048 71 0.00052
30-35 5442 61 0.00047
35-40 1071 15 0.00062
Total 194 0.002

[ Definition ] [ Step 1 ] [ Step 2 ] [ Step 3 ] [ Step 4 ] [ Step 5 ]