Bioequivalence and Bioavailability Forum

Hi BE-Proff,

❝ Is it possible using PowerTOST to calculate possiblity that upper and lower limits will be higher and lower than in previous study?

I don't know if PowerTOST provides the functionality but it isn't particularly difficult on the general level. The power is calculated as the probability difference P(point est. lower than some High limit) - P(point. est. lower than some Low limit), where the P's depend on sample size CV and GMR and actual limits.

But in practive you'll easily find yourself in trouble. If you have a CI of 0.85 -1.01 from a prior trial then your GMR is likely somewhere in between, but you don't have a solid basis for saying it is the point estimate (=sqrt(0.85*1.01)). So you might not have a good GMR-value to plug into the calculations of power for the next trial.