Formula
Customers who made at least one referral / Total eligible customers x 100
How to measure
Divide the count of customers who generated or shared a referral link at least once by the total customer base eligible for the program.
Why track it
Low participation, even with strong per-referral conversion, points to an awareness or incentive design problem rather than a channel quality problem.
Example
A referral program finds only 4% of eligible customers ever share their referral link, prompting a more visible in-app prompt.