---
title: "Behavioral vs declared customer data | Snowplow Signals"
description: "Declared data is what a customer tells you. Behavioral data is what they do. A profile needs both, and behavior is the half that changes by the minute."
source: https://signals.snowplow.io/learning/customer-profiles-and-identity/behavioral-vs-declared-customer-data
---

[Learning](https://signals.snowplow.io/learning) / [Customer profiles and identity](https://signals.snowplow.io/learning/customer-profiles-and-identity) 

# Behavioral vs declared customer data

Declared data is what a customer states about themselves, like preferences set at signup. Behavioral data is what they actually do, captured as events. Declared data ages; behavioral data keeps a profile current.

## Declared data

Declared data is what a customer tells you directly: the fields they filled in, the preferences they set, the plan they chose. It is accurate when given and easy to store, but it ages. People do not come back to update a form when their situation changes.

## Behavioral data

Behavioral data is what a customer does, captured as events: pages viewed, items added, searches run, features used. Nobody has to report it, and it reflects the present. The cost is that it arrives constantly and has to be collected and computed into something a profile can hold.

## Why a profile needs both

Declared data says who someone is and what they said they wanted. Behavioral data says what they are doing now. A profile on declared data alone describes a customer as they were at signup. Behavior is what keeps it describing the customer in front of you.

## Put it to work

* [Real-time attributes on Signals →](https://signals.snowplow.io/products/real-time-attributes)

## See it on your own traffic 

Add the SDK, define one attribute, and see an attribute updating against your own traffic in the first session. The free tier runs on the real engine: no card, no sales call.

[Start free](https://signals.snowplow.io/start) [Talk to an engineer](https://signals.snowplow.io/start?intent=engineer) 

More explainers in the [Learning Center →](https://signals.snowplow.io/learning)