I am writing to ask for help about the Mid-P calculation of the confidence limits for the standardized mortality ratio. Or any observed/expected ratio. I am familiar with the Mid-P for a binomial calculation but I am trying to understand how to calculate confidence intervals for a standardized mortality ratio under a Poisson distribution. I've found calculators with formulas such as OpenEpi but I haven't been able to replicate their results. And I haven't heard back from them yet.

I wanted to learn how the Mid-P for a SMR is calculated but I learn best with examples showing the various steps. I have not found any good illustrative examples in my google searches. A textbook example would be ideal.

I wanted to ask if you knew of a source, publication, or could send a simple example of the Mid-P CIs for a SMR that you think will help? Any suggestions would be greatly appreciated.

Sincerely,

Steve

I need help calculating the Mid-P of the confidence limits for the standardized mortality ratio, or any observed/expected ratio. I am familiar with the Mid-P for a binomial calculation but I am trying to understand how to calculate confidence intervals for a standardized mortality ratio under a Poisson distribution. I've found calculators with formulas such as OpenEpi but I haven't been able to replicate their results. Does anyone know of a source describing this calculation, or of a simple example that could help?