---
title: "About unique impression discrepancies in StackAdapt"
slug: "about-unique-impression-discrepancies-in-stackadapt"
description: "Learn what unique impression discrepancies are in StackAdapt data."
updated: 2025-06-26T11:43:16Z
published: 2025-06-26T11:43:16Z
canonical: "docs.supermetrics.com/about-unique-impression-discrepancies-in-stackadapt"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.supermetrics.com/llms.txt
> Use this file to discover all available pages before exploring further.

# About unique impression discrepancies in StackAdapt

StackAdapt adjusted its system to start tracking unique impressions at the Advertiser level around September 30, 2020.

If a query includes unique impression data from before that date, you might see differences in StackAdapt and Supermetrics for Advertisers, Campaign groups, and Campaigns data.