Profiles have a Decay rate field.
The Sitecore documentation explains it as:

...you can control how long an individual profile or pattern card is relevant to the Contact Behavior Profile by setting the decay rate. The decay rate is a percentage that expresses how relevant the profile will remain over time.

But that is not clear enough for me.

  1. When is the decay rate actually applied to the Contact Behaviour Profile?
  2. Daily, weekly, monthly?
  3. Or is that configurable somewhere?

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4 Answers 4


When is the decay rate actually applied to the Contact Behaviour Profile? Daily, weekly, monthly?

According to martin miles, and martin davies it is per interaction.

Is that configurable somewhere?

Martin Miles PDF presentation says at a given rate, which can be specified using the rules engine. I'll update answer as to how this works, when I get a chance.

A visitor’s behavior profile from their previous visit can now influence personalization rules in their current and future visit. Behavior Profiling are now stored both on the Interaction and Contact. Behavior Profile on the Contact can decay at a given rate per interaction.

Source: Martin Mile Presentation PDF (page 17)

Profiles items now have a "Decay Rate" field which specifies the percentage by which a contact's profile score should decrease at the start of each interaction.

Source: Martin Davies Blog Post


Decay rate is applied at the beginning of an interaction, after the contact's profile has been loaded.

To be specific, it occurs in the ApplyDecay processor of the intiailizeInteractionProfile pipeline.

Sitecore reads through every key in every profile one by one and applies the decay rate to the contacts existing scores.

  • I know it's old, but for anyone else who comes across this (and cares), the full flow goes: StartTrackingPipeline->InitializeTrackerPipeline->CreateVisit (processor) -> CreateVisitPipeline->intiailizeInteractionProfilePipeline->ApplyDecay. CreateVisit only calls CreateInteraction once per session, so "interaction" == session.
    – Jason
    Commented Sep 3, 2021 at 1:41

The Decay rate specifies how relevant the profile will remain over time. It means that visits that was performed in the past will be less relevant than current visit.

For example, if you want the past visit to be as relevant as current visit you can set the value to 0. Please refer to the following article:


Also please note that this field is not about a "time", but about profile "values" between site visits. Please consider reading the "Profile Decay" section of the following article for details:



At a higher level, think of decay rate the way that it is used in machine learning. The general idea is that the more recent the information is the more reliable it is.

In Sitecore, Decay Rate is computed using a half-life formula, where by 1 interaction is equal to 1 unit of time.

Real-world Example 1:

Consider a user browsing to the website of an athletic club that they are considering joining. After a few page views and interactions, this user is personalized and shown content geared towards a prospective member. The user is engaged and signs up for a membership.

Three weeks later, the user returns to the site. After a few page views and interactions, one might expect that this user would be personalized and shown content geared towards new members. This is where the Decay Rate comes in. If you are not using decay rates and you do not want to lose the data from your user's past interactions with the site, then from the moment your user returns your site he/she may still be shown prospective member content. If, however, you set up a decay rate, you don't lose any of that past interaction data and you still account for it in personalization. However the past data is worth less than the new data.

Real-world Example 2:

Another example is an e-commence site. Imagine you have a site that sells cellphones. If your visitor comes to the site and searches for phones and clicks on a bunch of the new ones then they are personalized and shown the newest phones. Assume that your user buys the newest Samsung Galaxy phone and leaves the site.

When your user returns, do you think your user is still interested in buying a new phone? Maybe, but the user searches for phone accessories. Now, what is the ideal experience to personalize the user with? Should they see iPhone accessories in our personalized advertisement components, or should we remember and account for the fact that on their last visit they looked for the latest tech, bought a new android phone, and chose the manufacturer Samsung? If we account for their previous visit's interactions, we can now show them phone accessories that best match the other data that we have from their last visit. As such, we may display the latest Samsung Galaxy phone compatible accessories first, followed by the latest in android and universal accessories, then older accessories and so on.

Summing it up:

The Decay Rate enables you to control the Rate at which past interactions decrease in value over time, using a basic half-life (1 interaction equals 1 unit of time) formula.

By effectively using Decay Rates, you empower your site to deliver more accurately personalized content, thereby improving engagement scores.

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