Definition

A disproportionality measure comparing the proportion of a specific event for a drug versus the proportion for all other drugs in the database.

Example

If 10% of Drug X reports mention rhabdomyolysis but only 1% of all other drug reports mention it, PRR = 10/1 = 10, suggesting a potential signal.

Regulatory source

EU GVP Module IX, EudraVigilance

Common mistakes

Using PRR without considering case counts. A PRR of 10 based on 2 cases is less meaningful than PRR of 3 based on 500 cases.

Inspector question

What PRR threshold do you use for signal detection? How do you account for sample size?

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