Ask for the equation of Incidence Rate Ratio (IRR) calculation

[Tewei Ho]

Hello everyone,

For the purpose of research, I hope to know the equation of Incidence Rate Ratio (IRR) calculation in Stata, especially in 95%CI.
However, I can't find any document or reference of it.
The attached file is a kind of equation of IRR.
Could somebody give me the equation of Stata for the study.
Many thanks.

[Joseph Coveney]

I'm not sure what your attachment is all about, but you can find formulas that Stata uses for computing IRR and confidence intervals for unstratified data by typing "help epitab" at Stata's command prompt, and then clicking on the hyperlink to the user's manual in the pop-up window. (The hyperlink is just beneath the "Title" on the pop-up help file window.) In the epitab entry in the user's manual, click on the hyperlink header titled "Methods and formulas". Do analogously for formulas used by relevant estimation commands (poisson etc.).