Apple's iOS framework, effective April 2021, that requires apps to ask permission before tracking users across other companies' apps and websites or accessing the IDFA. Opt-in rates have settled around a quarter of users. ATT reduced the precision of iOS targeting and attribution across the industry and was the proximate cause of the shift to SKAdNetwork, modeled conversions, and Marketing Mix Modeling.
Used in The Signal
Cite this entry:
Agency Echelon. "App Tracking Transparency." Agency Echelon Reference, reviewed September 2026. https://agencyechelon.com/reference/glossary/app-tracking-transparency/