I am running an analysis in a large population registry where individuals enter and leave the dataset at different time points.
When i estimated the IRR between two distinct groups and a health outcome, and then a HR, I am finding a small difference (IRR 2.18, HR 2.01).
Shouldn't they have been identical, since I am not adjusting for any covariates, etc? Are there any reasons that could explain why they are not identical?
Any thoughts would be appreciated.
When i estimated the IRR between two distinct groups and a health outcome, and then a HR, I am finding a small difference (IRR 2.18, HR 2.01).
Shouldn't they have been identical, since I am not adjusting for any covariates, etc? Are there any reasons that could explain why they are not identical?
Any thoughts would be appreciated.