Q: 27% of our leads were silently rejected as duplicates — where were they coming from?

Q: 27% of our leads were silently rejected as duplicates — where were they coming from?

A: Duplicate rejection means the same person submitted more than once, and the advertiser only pays for the first. We traced one nutra campaign where 27% of leads bounced as dupes.

The affiliate added a hash check on their own form (storing a one-way fingerprint of email + phone) before sending leads onward. The duplicates split into three causes:
— 14% were users double-clicking the submit button (a front-end bug firing two leads)
— 9% were the same users retargeted across two of their own campaigns, submitting twice
— 4% were genuinely recycled data from a traffic source

The double-click bug was a one-line fix (disable the button on submit). The retargeting overlap they solved with a 30-day suppression list across campaigns.

Result: duplicate rejection fell from 27% to 6%, recovering most of the lost payout with zero new traffic spend.

Short version: most 'duplicate' rejections are your own double-fires and campaign overlap — dedupe on your side before blaming the source.

Still stuck? Drop your case in the comments.