EV referral codes
One code.
Drawn fairly,
and measured.
Owners contribute their referral code. Visitors get one at random — not whoever paid, not whoever arrived first. The draw from the pool is uniform, and we measured it rather than claiming it.
The draw, measured
400,000 draws across 10,182 codes. Every bar is one code's share. Flat is the point.
The obvious way to pick a random row is biased, and badly: the first approach we tried gave the luckiest code 12.7× the average and never served 2.4% of codes at all. We measured it, threw it away, and built the one above instead. Share a code here and it competes on the same terms as every other code in the pool.
The site owner's code is in the same pool as everyone else's. When the promo is on, it gets a small fixed share of requests — never more than 5% — before the fair draw; when it is off, it competes like any other code.Why, and what that means →