De-duplication best practice

What is de-duplication? Also called conditional tracking or tracking attribution, refers to paying commission if the affiliate was the last paid marketing channel.


Using automatic de-duplication or "conditional tracking" is done by appending a parameter to the clickthrough URL (click append) when sending a visitor to any page on the merchant’s website. For example: ‘source=commissionfactory’. The parameter and value is recognised by the merchant’s site and is used to trigger the writing of a local cookie which stores the source of the visitor.

The source could be Commission Factory or any other advertising channel that the merchant wishes to de-dupe against, for example paid social.  Subsequently, if the customer is sent back to the merchant by one of the other advertising channels then the local cookie should be overwritten with one for the last referring advertising channel. ​The advertiser only displays the conversion tracking code when an affiliate had the last touch in the custom journey before purchase. 

We have some specific code examples on how this can be implemented, but how this is done will depend on your tracking is implemented. Some shopping carts have more limited functionality than others, so please ask your developer to review.


Advertiser A added a click append to their URL for each online channel to define where the customer had arrived from, for example:

They then wrote a script to place a local cookie on the user’s computer triggered by the presence of the click append.

They then established a rule that the click append source ID would be overwritten on a last referrer basis.

For a customer clicking through via a PPC ad, who then browses and returns via a Commission Factory publisher the source id “?source=ppc” would be replaced with “?source=commissionfactory”.

The tracking tag logic at the sale confirmation page would recognise the “?source=commissionfactory” click append and show only the Commission Factory tracking code, thus correctly awarding the sale to the last referring channel.

All traffic must be tagged to ensure accurate cross-channel de-duplication. The last referrer wins method must be used cross all channels to ensure fair de-duping.

If automated de-duplication is not possible, then this can be done via validation process, however it will be more time consuming for the advertiser to manage and also to manage in bound support queries around why orders are voided.

Which online channels should advertisers de-duplicate against?

Do not de-duplicate against organic search/direct traffic: these are typically non paid channels and along with brand paid search will often be the last visit in a user’s journey. It's important to be respective of the channel and your partners.

Communication with publishers

Your de-duplication policy must be clearly communicated with your publishers. This can be added to the program description page. If you are live and implement a new policy around this, then we also recommend outlining the policy via a message to all your publishers via the message centre.

 Key Points

  • Use a click append and local cookie solution to control sale de-duplication
  • Consider the impact of de-duplicating against other marketing channels (eg. conversion rate decrease)
  • Be mindful of the influence a publisher can make on your customers purchase decision making
  • Display your de-duplication policy within your program terms
  • Communicate any changes to your policy in advance of your programme