Feb 5, 2019

Switching probabilistic matching off by default (for new apps and trackers)

From today, when a new app is created in the Adjust dashboard, probabilistic matching (a method of identifying users) will be switched off by default.

Previously, probabilistic matching was set to on for all clients creating an app. Now, new apps will have probabilistic matching set to off, but can manually switch it on if they would like to.

Furthermore, for apps that were previously added before this time, existing tracker settings have been migrated to on. However, any new trackers created will be automatically off.


When you create a new app and navigate to the attribution settings, within ‘Click Based’, you will see a probabilistic matching toggle set to off, and which you can manually switch to on. The toggle is available to all customers, and can also be accessed for current apps within the same settings.

For more technical information, please read our documentation here (for Campaign Wizard specific docs, please click here). For more on why we’re doing this, click here to be taken to an article written by our CTO, Paul H. Müller, or read our summary below.

Why are we making this change?

Probabilistic matching has become increasingly exploited by an ad fraud method known as ‘Click Spamming’.

Over 15% of attributions on Android are matched by probabilistic matching, and more than 20% on iOS.

This is a large chunk of activity that is matched by identifiers which are increasingly common, and which fraudsters are developing better ways of taking advantage of.

So, by switching probabilistic matching off, we’re providing our clients with a simple means to block click spamming from affecting their campaigns. For more, click here.