Rates

When FDA weighs probable risks, it looks at how often harmful events occur, not only at whether they occur. Presenting rates consistently, with the denominator stated, makes a benefit-risk argument easier to follow and compare.

For purposes of this guidance, “rates” means the number of harmful events per patient or number of harmful events per unit of time.

FDA guidance: Factors to Consider When Making Benefit-Risk Determinations in Medical Device Premarket Approval and De Novo Classifications (August 2019), Footnote 11