Comparing Two Person-Time Rates
(PersonTime2)
For
a single person-time table comparing exposed and nonexposed,
the notation is depicted in Table 15-10. Estimates of the incidence rate ratio (IRR),
the incidence rate difference (IRD), their confidence intervals, and test for
interaction are presented. Approximate confidence interval methods are provided but it is important to note that there are
better confidence interval methods when the data are sparse.
Table 15-10. Notation
for comparing exposed and nonexposed with person-time
denominators.
|
Exposed |
Nonexposed |
|
Cases |
a |
b |
m1 |
Person-time |
n1 |
n0 |
n |
Estimated
incidence rate in the exposed =