I wondered if it is possible to calculate the inverse of an IRR like we can for odds ratio (inverse = 1/x).
IRR = 1.40, 95% CI = 1.18 -1.65
Inverse IRR: = 1/1.40 = 0.71
Thank you (Using Stata 11)
Yes, that just gives you the rate ratio with 1 as the referent group instead of 0 (for a binary variable) or for a one unit decrease in the variable (for a continuous variable) exactly as with a risk ratio or odds ratio.